Merge pull request open-source-parsers#26 from alex-ac/master

Fix CMake subproject behaviour.

Sweet. But doesn't this assume that people call the subproject `jsoncpp`? It used to be `json-cpp`.

Author: cdunn2001

CMakeLists.txt

@@ -71,7 +71,7 @@ macro(UseCompilationWarningAsError)
 endmacro() 
 
 # Include our configuration header
-INCLUDE_DIRECTORIES( ${CMAKE_SOURCE_DIR}/include )
+INCLUDE_DIRECTORIES( ${jsoncpp_SOURCE_DIR}/include )
 
 if ( MSVC )
     # Only enabled in debug because some old versions of VS STL generate