Tidy up tests, build scripts, and documentation:

* Concepts split up into individual files
* Function definitions moved to .ipp files
* Add more tests to fill gaps in coverage
* Fix documentation Xsl

include/beast/http/impl/basic_headers.ipp

@@ -8,8 +8,6 @@
 #ifndef BEAST_HTTP_IMPL_BASIC_HEADERS_IPP
 #define BEAST_HTTP_IMPL_BASIC_HEADERS_IPP
 
-#include <beast/type_check.hpp>
-
 namespace beast {
 namespace http {
 

include/beast/http/impl/basic_parser_v1.ipp

@@ -8,6 +8,8 @@
 #ifndef BEAST_HTTP_IMPL_BASIC_PARSER_V1_IPP
 #define BEAST_HTTP_IMPL_BASIC_PARSER_V1_IPP
 
+#include <beast/buffer_concepts.hpp>
+
 namespace beast {
 namespace http {
 
@@ -32,8 +34,11 @@ keep_alive() const
 // Implementation inspired by nodejs/http-parser
 
 template<bool isRequest, class Derived>
-template<class ConstBufferSequence, class>
-std::size_t
+template<class ConstBufferSequence>
+typename std::enable_if<
+    ! std::is_convertible<ConstBufferSequence,
+        boost::asio::const_buffer>::value,
+            std::size_t>::type
 basic_parser_v1<isRequest, Derived>::
 write(ConstBufferSequence const& buffers, error_code& ec)
 {

include/beast/http/impl/message_v1.ipp

@@ -10,7 +10,6 @@
 
 #include <beast/http/rfc2616.hpp>
 #include <beast/http/detail/has_content_length.hpp>
-#include <beast/type_check.hpp>
 #include <boost/optional.hpp>
 #include <stdexcept>
 

include/beast/http/impl/read.ipp

@@ -11,6 +11,7 @@
 #include <beast/http/parser_v1.hpp>
 #include <beast/bind_handler.hpp>
 #include <beast/handler_alloc.hpp>
+#include <beast/stream_concepts.hpp>
 #include <cassert>
 
 namespace beast {

include/beast/http/impl/write.ipp

@@ -13,9 +13,10 @@
 #include <beast/http/detail/has_content_length.hpp>
 #include <beast/buffer_cat.hpp>
 #include <beast/bind_handler.hpp>
+#include <beast/buffer_concepts.hpp>
 #include <beast/handler_alloc.hpp>
+#include <beast/stream_concepts.hpp>
 #include <beast/streambuf.hpp>
-#include <beast/type_check.hpp>
 #include <beast/write_streambuf.hpp>
 #include <boost/asio/write.hpp>
 #include <boost/logic/tribool.hpp>