AUI-1276 Unit test for char counter module

This is a unit test for the CharCounter module, which had no tests up until now.
AUI-1276 - SF
AUI-1284 Use cssClass attribute from WidgetCssClass instead of separated atributes for CSS class names in Button
AUI-1284 Source formatting
AUI-1284 ButtonGroup still needs the work around to add btn-default