json cJSON

This example exercises the cJSON implementation at apps/netutils/json. This example contains logic taken from the cJSON project:

http://sourceforge.net/projects/cjson/

The example corresponds to SVN revision r42 (with lots of changes for NuttX coding standards). As of r42, the SVN repository was last updated on 2011-10-10 so I presume that the code is stable and there is no risk of maintaining duplicate logic in the NuttX repository.