- 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).

src/test_lib_json/CMakeLists.txt

@@ -0,0 +1,21 @@
+
+IF(JSONCPP_LIB_BUILD_SHARED)
+  ADD_DEFINITIONS( -DJSON_DLL )
+ENDIF(JSONCPP_LIB_BUILD_SHARED)
+
+ADD_EXECUTABLE( jsoncpp_test 
+                jsontest.cpp
+                main.cpp
+                )
+
+TARGET_LINK_LIBRARIES(jsoncpp_test jsoncpp_lib)
+
+# Run unit tests in post-build
+# (default cmake workflow hides away the test result into a file, resulting in poor dev workflow?!?)
+IF(JSONCPP_WITH_POST_BUILD_UNITTEST)
+    ADD_CUSTOM_COMMAND( TARGET jsoncpp_test
+				        POST_BUILD
+				        COMMAND jsoncpp_test)
+ENDIF(JSONCPP_WITH_POST_BUILD_UNITTEST)
+
+SET_TARGET_PROPERTIES(jsoncpp_test PROPERTIES OUTPUT_NAME jsoncpp_test)