Build for 10.6 and i386 restored.

Build against latest SDK.
Set m_searchers to the proper type
Added Unit Test bundle
Implemented JSONDocument for easy JSON parsing

Currently just a thin wrapper around NSJSONSerialization
Added JSONDecoder as an alternate decoder for JSON data, if the OS does not supply NSJSONSerialization.

JSONDecoder is dual-licensed, BSD and Apache, so it is compatible with the current VideoMonkey license.