updated buttons and clicking to use new styling patterns
get rid of :listener attribute in swt_button
updated mock with clickable and other minor improvements
whoops almost missed untracked file
and ... put the indentation back
Spec fix for link
updated various method to match comments
Merge branch 'button_style' of https://github.com/shoes/shoes4 into button_style
minor fix of link_spec
Merge pull request #803 from shoes/button_style

Added styling and clicking to buttons (check, radio, and button)

Changelog: improvement