Check that file exist before opening

[stoivo]

close #646

[randy3k]

Let's also tag a new release after merging this~

[stoivo]

A new release? should I make it

Changes since 2.14.1:

  Fix:
   - Show open inline diff if it already open form status dashboard
   - Push tags command is not blocking
   - added self.get_short_hash to honor core.abbrev settings (#642)

  Other:
   - Sort branches by recent commited (#632)
   - Check that file exist before opening (#648)

  Improvement:
   - Remove some clutter from debug.log (#635)
   - Warn the user when we have permission error (#636)
   - it is not necessary to check if HEAD is rebased
   - use message_dislog for show the messages
   - do not allow squashing merges

  Contributors:
   - Simon
   - Juan Pumarino
   - Pavel Savchenko
   - Vlad Tsepelev
   - Randy Lai

New commit a then a new tag

[randy3k]

Sure!