Standardize header names and file locations

This is both a really big and a really small commit. It is small in
that it only contains renaming, moving and modification of include
directives caused by this.

It is really big in the obvious way of touching something like 200
files.

The new rules for naming files is simple: headers use the `.hpp`
extension. The rules for physical file layout is still kinda in
progress, but the basics are also simple:
 * Significant parts of functionality get their own subfolder
   * Benchmarking is in `catch2/benchmark`
   * Matchers are in `catch2/matchers`
   * Generators are in `catch2/generators`
   * Reporters are in `catch2/reporters`
   * Baseline testing facilities are in `catch2/`
 * Various top level folders also contain `internal` subfolder,
   with files that users probably do not want to include directly,
   at least not until they have to write something like their own
   reporter.
    * The exact files in these subfolders is likely to change later
      on

Note that while some includes were cleaned up in this commit, it
is only the low hanging fruit and further cleanup using automatic
tooling will happen later.

Also note that various include guards, copyright notices and file
headers will also be standardized later, rather than in this commit.

src/catch2/internal/catch_stream.cpp

@@ -0,0 +1,187 @@
+/*
+ *  Created by Phil on 17/01/2011.
+ *  Copyright 2011 Two Blue Cubes Ltd. All rights reserved.
+ *
+ *  Distributed under the Boost Software License, Version 1.0. (See accompanying
+ *  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ *
+ */
+
+#include <catch2/internal/catch_common.hpp>
+#include <catch2/internal/catch_enforce.hpp>
+#include <catch2/internal/catch_stream.hpp>
+#include <catch2/internal/catch_debug_console.hpp>
+#include <catch2/catch_stringref.hpp>
+#include <catch2/internal/catch_singletons.hpp>
+
+#include <cstdio>
+#include <iostream>
+#include <fstream>
+#include <sstream>
+#include <vector>
+#include <memory>
+
+namespace Catch {
+
+    Catch::IStream::~IStream() = default;
+
+    namespace Detail { namespace {
+        template<typename WriterF, std::size_t bufferSize=256>
+        class StreamBufImpl : public std::streambuf {
+            char data[bufferSize];
+            WriterF m_writer;
+
+        public:
+            StreamBufImpl() {
+                setp( data, data + sizeof(data) );
+            }
+
+            ~StreamBufImpl() noexcept {
+                StreamBufImpl::sync();
+            }
+
+        private:
+            int overflow( int c ) override {
+                sync();
+
+                if( c != EOF ) {
+                    if( pbase() == epptr() )
+                        m_writer( std::string( 1, static_cast<char>( c ) ) );
+                    else
+                        sputc( static_cast<char>( c ) );
+                }
+                return 0;
+            }
+
+            int sync() override {
+                if( pbase() != pptr() ) {
+                    m_writer( std::string( pbase(), static_cast<std::string::size_type>( pptr() - pbase() ) ) );
+                    setp( pbase(), epptr() );
+                }
+                return 0;
+            }
+        };
+
+        ///////////////////////////////////////////////////////////////////////////
+
+        struct OutputDebugWriter {
+
+            void operator()( std::string const&str ) {
+                writeToDebugConsole( str );
+            }
+        };
+
+        ///////////////////////////////////////////////////////////////////////////
+
+        class FileStream : public IStream {
+            mutable std::ofstream m_ofs;
+        public:
+            FileStream( StringRef filename ) {
+                m_ofs.open( filename.c_str() );
+                CATCH_ENFORCE( !m_ofs.fail(), "Unable to open file: '" << filename << "'" );
+            }
+            ~FileStream() override = default;
+        public: // IStream
+            std::ostream& stream() const override {
+                return m_ofs;
+            }
+        };
+
+        ///////////////////////////////////////////////////////////////////////////
+
+        class CoutStream : public IStream {
+            mutable std::ostream m_os;
+        public:
+            // Store the streambuf from cout up-front because
+            // cout may get redirected when running tests
+            CoutStream() : m_os( Catch::cout().rdbuf() ) {}
+            ~CoutStream() override = default;
+
+        public: // IStream
+            std::ostream& stream() const override { return m_os; }
+        };
+
+        ///////////////////////////////////////////////////////////////////////////
+
+        class DebugOutStream : public IStream {
+            std::unique_ptr<StreamBufImpl<OutputDebugWriter>> m_streamBuf;
+            mutable std::ostream m_os;
+        public:
+            DebugOutStream()
+            :   m_streamBuf( std::make_unique<StreamBufImpl<OutputDebugWriter>>() ),
+                m_os( m_streamBuf.get() )
+            {}
+
+            ~DebugOutStream() override = default;
+
+        public: // IStream
+            std::ostream& stream() const override { return m_os; }
+        };
+
+    }} // namespace anon::detail
+
+    ///////////////////////////////////////////////////////////////////////////
+
+    auto makeStream( StringRef const &filename ) -> IStream const* {
+        if( filename.empty() )
+            return new Detail::CoutStream();
+        else if( filename[0] == '%' ) {
+            if( filename == "%debug" )
+                return new Detail::DebugOutStream();
+            else
+                CATCH_ERROR( "Unrecognised stream: '" << filename << "'" );
+        }
+        else
+            return new Detail::FileStream( filename );
+    }
+
+
+    // This class encapsulates the idea of a pool of ostringstreams that can be reused.
+    struct StringStreams {
+        std::vector<std::unique_ptr<std::ostringstream>> m_streams;
+        std::vector<std::size_t> m_unused;
+        std::ostringstream m_referenceStream; // Used for copy state/ flags from
+
+        auto add() -> std::size_t {
+            if( m_unused.empty() ) {
+                m_streams.push_back( std::unique_ptr<std::ostringstream>( new std::ostringstream ) );
+                return m_streams.size()-1;
+            }
+            else {
+                auto index = m_unused.back();
+                m_unused.pop_back();
+                return index;
+            }
+        }
+
+        void release( std::size_t index ) {
+            m_streams[index]->copyfmt( m_referenceStream ); // Restore initial flags and other state
+            m_unused.push_back(index);
+        }
+    };
+
+    ReusableStringStream::ReusableStringStream()
+    :   m_index( Singleton<StringStreams>::getMutable().add() ),
+        m_oss( Singleton<StringStreams>::getMutable().m_streams[m_index].get() )
+    {}
+
+    ReusableStringStream::~ReusableStringStream() {
+        static_cast<std::ostringstream*>( m_oss )->str("");
+        m_oss->clear();
+        Singleton<StringStreams>::getMutable().release( m_index );
+    }
+
+    auto ReusableStringStream::str() const -> std::string {
+        return static_cast<std::ostringstream*>( m_oss )->str();
+    }
+
+
+    ///////////////////////////////////////////////////////////////////////////
+
+
+#ifndef CATCH_CONFIG_NOSTDOUT // If you #define this you must implement these functions
+    std::ostream& cout() { return std::cout; }
+    std::ostream& cerr() { return std::cerr; }
+    std::ostream& clog() { return std::clog; }
+#endif
+}