- New CMake based build system. Based in part on contribution from

Igor Okulist and Damien Buhl (Patch #14). Added support for running
tests and building with DLL on Windows.
- added missing JSON_API
- Visual Studio DLL: suppressed warning "C4251: <data member>: <type> 
needs to have dll-interface to be used by..." via pragma push/pop
in json-cpp headers.
- New header json/version.h now contains version number macros
(JSONCPP_VERSION_MAJOR, JSONCPP_VERSION_MINOR, JSONCPP_VERSION_PATCH
and JSONCPP_VERSION_HEXA). While this header is generated by CMake,
it is committed to ease build with alternate build system 
(CMake only update the file when it changes avoid issues with VCS).

include/json/value.h

@@ -21,6 +21,13 @@
 #  include <cpptl/forwards.h>
 # endif
 
+// Disable warning C4251: <data member>: <type> needs to have dll-interface to be used by...
+#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+# pragma warning(push)
+# pragma warning(disable:4251)
+#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+
+
 /** \brief JSON (JavaScript Object Notation).
  */
 namespace Json {
@@ -1109,4 +1116,9 @@ public: // overridden from ValueArrayAllocator
 } // namespace Json
 
 
+#if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+# pragma warning(pop)
+#endif // if defined(JSONCPP_DISABLE_DLL_INTERFACE_WARNING)
+
+
 #endif // CPPTL_JSON_H_INCLUDED