Draft: JSON

I wanted to always try to write a simple glib'y JSON parser. Now I did.
And because I don't want to lose it, I'll put it here.
I don't have an actual need for it (yet), but maybe someone else has.

The goal is to write a simple parser implementing a Reader API that fits in a single source file.
The parser should also be secure (no buffer overflows plz).
And it should be easy to use for straightforward cases, so it can easily be used for debugging tools and testing.
I do not aim at all for bindability, because every language has way better native JSON parsers than bindings could ever come up with.