* clutter/clutter-json.h: Header for including the JSON
parsing and data types.
* clutter/json/json-types.h: Add JSON_NODE_VALUE_TYPE() macro.
* clutter/json/Makefile.am: Install the JSON headers into a
private location. This might change in the future, and might
also cause collisions if you're using JSON-GLib and Clutter
at the same time, so be warned.