* If the submit_branch has a public_branch set, use that in the submission (this matches the behaviour of "bzr send").
* Check for uncommitted changes in the local tree before checking that the public branch location is up to date.
* Make the --message/-m argument of "bzr pqm-submit" mandatory.
* If a branch location is given on the command line, it must specify a branch rather than a location inside the branch.
* Make use of new bzrlib infrastructure from bzr-1.3.