Log Message:
Update to 2.1.0 for compatability with updated devel/bzr version.
From Jan Danielsson in private mail.  Miscellaneous changes, including:

* (Gordon Tyler) shell now accepts --directory
* shell now run qbzr commands in a subprocess.
* (Max Bowsher) fetch-ghosts now works again.  And has tests.
* conflict-diff no longer requires a single file to be specified.  Multiple
  files or no files can be specified.