gcalendar.R
Events such as <Return>, <FocusOut> and <Button-1> were not causing
any change in svalue for gcalendar.
Add handers for <Return> and <FocusOut> in the text widget.
Invoke set_value() from the <Button-1> binding for calendar day,
so that invoke_change_handler() is called.
Merge pull request #5 from maclean/master

Fixes to gcalendar.R