Auto detects function declarations

Functions passed as strings are auto-detected and converted to functions.  MouseOver and MouseOut event actions default to sending x,y,value,color values to shiny.  If a different function has been set or if the value is set to null then no function is installed.

Beginning work on automatically setting radial gradients on 3d plots.

Still needed: draggable functionality.
Automatically sets gradients on points if options3d is enabled
Further enhancements

-cleanUp function iterates over JSON input to convert functions from strings to functions
-checkNested function checks for the existence of an element within nested objects
-radial gradients are only applied to 3d chart colors