LSL updates

Added JSON LSL stuff according to [server release notes](http://wiki.secondlife.com/w/index.php?title=Release_Notes%2FSecond_Life_RC_Magnum%2F13&diff=1178338&oldid=1178252) and [json usage page](http://wiki.secondlife.com/wiki/Json_usage_in_LSL).

Added LSL snippets file.