Merge patch #18

https://sf.net/p/jsoncpp/patches/18/

Conflicts:
	src/jsoncpp/include/json/value.h
	src/jsoncpp/include/json/writer.h
	src/jsoncpp/json_value.cpp
	src/jsoncpp/json_writer.cpp
Fixes for json null byte patch to make it not warn.
Add a simple test for a null byte in a string.
General gitignore fixups.
Merge branch 'jsoncpp-null-bytes'