JQM component event basics + "tap".

Added support for "tap" JQM event
(http://api.jquerymobile.com/category/events/) wherever there was
support for click implemented in JQM4GWT. "taphold" is implemented but
not added to any widget.

Other event types need to be added as well (should be easy now); maybe
it would be a good idea to add all those at JQMWidget level - as JQM
doesn't specify each event for what widget is meant...