send undo and clrPaper events to html5-client, and enable html5-client to see square while Ctrl keypressed
remove unnecessary changes
After clearShape,currentshape should not be null
Merge pull request #224 from SenecaCDOT-BigBlueButton/Activate-Undo-ClrPaper-Events

Activate "undo" and  "clrpaper" events
Merge remote branch 'downstream/html5-bridge' into html5-bridge