Renamed include/ folder to gsl/ to make including the library consistent

whether using it from the development folder, from the installation
folder or from being copied into a project. 

    #include <gsl/gsl.h>

Updated headers/tests/instructions/cmake build accordingly

This PR should address https://github.com/Microsoft/GSL/issues/277 (less
the renaming of gsl itself)

CMakeLists.txt

@@ -3,10 +3,10 @@ cmake_minimum_required(VERSION 2.8.7)
 project(GSL CXX)
 
 set(GSL_HEADERS
-    "include/gsl.h"
-    "include/gsl_assert.h"
-    "include/span.h"
-    "include/string_span.h"
+    "gsl/gsl.h"
+    "gsl/gsl_assert.h"
+    "gsl/span.h"
+    "gsl/string_span.h"
 )
 
 include_directories(

README.md

@@ -6,10 +6,10 @@ This repo contains Microsoft's implementation of GSL.
 
 The library includes types like `span<T>`, `string_span`, `owner<>` and others.
 
-The entire implementation is provided inline in the headers under the [include](./include) directory. The implementation generally assumes a platform that implements C++14 support. There are specific workarounds to support MSVC 2013 and 2015.
+The entire implementation is provided inline in the headers under the [gsl](./gsl) directory. The implementation generally assumes a platform that implements C++14 support. There are specific workarounds to support MSVC 2013 and 2015.
 
-While some types have been broken out into their own headers (e.g. [include/span.h](./include/span.h)),
-it is simplest to just include [gsl.h](./include/gsl.h) and gain access to the entire library.
+While some types have been broken out into their own headers (e.g. [gsl/span.h](./gsl/span.h)),
+it is simplest to just include [gsl/gsl.h](./gsl/gsl.h) and gain access to the entire library.
 
 > NOTE: We encourage contributions that improve or refine any of the types in this library as well as ports to
 other platforms. Please see [CONTRIBUTING.md](./CONTRIBUTING.md) for more information about contributing.
@@ -66,5 +66,20 @@ All tests should pass - indicating your platform is fully supported and you are
 ## Using the libraries
 As the types are entirely implemented inline in headers, there are no linking requirements.
 
-Just place the contents of the [include](./include) directory within your source tree so it is available
-to your compiler, then include the appropriate headers in your program, and away you go!
+You can copy the [gsl](./gsl) directory into your source tree so it is available
+to your compiler, then include the appropriate headers in your program.
+
+Alternatively set your compiler's *include path* flag to point to the GSL development folder (`c:\GSL` in the example above) or installation folder (after running the install). Eg.
+
+MSVC++
+
+    /I c:\GSL
+
+GCC/clang
+
+    -I$HOME/dev/GSL
+    
+
+Include the library using:
+
+    #include <gsl/gsl.h>

tests/CMakeLists.txt

@@ -9,7 +9,7 @@ endif()
 add_subdirectory(unittest-cpp)
 
 include_directories(
-    ../include
+    ..
     ./unittest-cpp
 )
 
@@ -33,7 +33,7 @@ else()
 endif()
 
 function(add_gsl_test name)
-    add_executable(${name} ${name}.cpp ../include/gsl.h ../include/gsl_assert.h ../include/gsl_util.h ../include/multi_span.h ../include/span.h ../include/string_span.h)
+    add_executable(${name} ${name}.cpp ../gsl/gsl.h ../gsl/gsl_assert.h ../gsl/gsl_util.h ../gsl/multi_span.h ../gsl/span.h ../gsl/string_span.h)
     target_link_libraries(${name} UnitTest++)
     install(TARGETS ${name}
         RUNTIME DESTINATION bin

tests/assertion_tests.cpp

@@ -15,7 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h> 
-#include <gsl.h>
+#include <gsl/gsl.h>
 
 using namespace gsl;
 

tests/at_tests.cpp

@@ -15,7 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h> 
-#include <gsl.h>
+#include <gsl/gsl.h>
 #include <vector>
 #include <initializer_list>
 

tests/bounds_tests.cpp

@@ -15,7 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h> 
-#include <multi_span.h>
+#include <gsl/multi_span.h>
 #include <vector>
 
 using namespace std;

tests/byte_tests.cpp

@@ -15,7 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h>
-#include <gsl_byte.h>
+#include <gsl/gsl_byte.h>
 
 #include <iostream>
 #include <list>

tests/multi_span_tests.cpp

@@ -15,7 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h>
-#include <multi_span.h>
+#include <gsl/multi_span.h>
 
 #include <iostream>
 #include <list>

tests/notnull_tests.cpp

@@ -15,7 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h> 
-#include <gsl.h>
+#include <gsl/gsl.h>
 #include <vector>
 
 using namespace gsl;

tests/owner_tests.cpp

@@ -15,7 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h> 
-#include <gsl.h>
+#include <gsl/gsl.h>
 #include <functional>
 
 using namespace gsl;

tests/span_tests.cpp

@@ -15,7 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h>
-#include <span.h>
+#include <gsl/span.h>
 
 #include <iostream>
 #include <list>

tests/strided_span_tests.cpp

@@ -15,7 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h> 
-#include <multi_span.h>
+#include <gsl/multi_span.h>
 
 #include <string>
 #include <vector>

tests/string_span_tests.cpp

@@ -16,7 +16,7 @@
 
 #include <UnitTest++/UnitTest++.h>
 #include <cstdlib>
-#include <string_span.h>
+#include <gsl/string_span.h>
 #include <vector>
 
 using namespace std;

tests/utils_tests.cpp

@@ -15,7 +15,7 @@
 ///////////////////////////////////////////////////////////////////////////////
 
 #include <UnitTest++/UnitTest++.h>
-#include <gsl.h>
+#include <gsl/gsl.h>
 #include <functional>
 
 using namespace gsl;