Improvements for the "Check for modifications" dialog

Hello!

There are three things about the above mentioned dialog which could, IMHO, be
improved:

1. One should be able to commit a file. I can update, revert
   and such, but not commit. Is there a reason for that?
2. After updating the local copy of a remotely modified file
   the list should be updated as well to reflect the new
   working copy state. Currently the just updated file
   is still marked as "remotely modified".
3. Add an option to the dialog to automatically check the repository
   regularly.

Christian