Optional tag after commit

In the commit dialog we should add a "tag after commit"-checkbutton + text-area where we set the version-tag. (I think using the same style as you've done with Author and Fixes).

Then we have the option to do a commit and in the same way tag the commited tree with our desired version.

If the issue should arise that we DO want to tag a modified tree, without those modifications we could add a separate "bzr tag" in the future.

See documentation:

http://doc.bazaar-vcs.org/bzr.dev/en/user-reference/bzr_man.html#tag
Section 3.7.2 "Tagging a release" http://doc.bazaar-vcs.org/bzr.dev/en/user-guide/index.html

See also

http://doc.bazaar-vcs.org/bzr.dev/en/user-reference/bzr_man.html#tags_

Scenario:
Niklas works on his project and want to create a release. 0.9.0. He uses the "tag-feature" to set the version and pushes the code to Launchpad.