Added new cooccurence widget (pure html + js), added mldb.values function to fetch data for it

Added html+js cooccurence widget
Updated mldb to include values() function to fetch lexicon values
Fixed potential bug in MLDB browser version when no callback is
supplier - let to 'undefined callback' in wrapper modules.
Updated widgets.css for new widget
Added functions to mldbtest roxy controller to test new widget
Added page to populate database with movies for cooccurence widget demo