Implement building with CMake.

Moved code for the cfacter executable under the exe directory.
Moved code for the cfacter shared library under the lib directory.
Moved the rapidjson code to be under the lib directory for now (probably belongs in a shared location).
Fix build on OSX.

Ignore Clang warning treated as error coming from rapidjson.
Merge branch 'cmake' of https://github.com/peterhuene/cfacter into peterhuene-cmake

Conflicts:
	Makefile
	lib/cfacterimpl.cc
	lib/cfacterlib.cc
Restore cpplint and cppcheck targets