Slicer/Slicer — pull request #144 by dstoup (2014-06-06 12:58:49+00:00)
Title: BUG: Persist 'dont show message' selection when deleting markups

This fix addresses Mantis item #3663. The ctkMessageBox expects a
ButtonRole of AcceptRole. Created a custom button for 2 reasons.
First, it allows us to set the correct role and secondly a "Delete"
and "Delete All" button more clearly aligns with the action being
performed.