hg flow does not work for feature branches with '#' in the name

Steps to reproduce:

1. init repository
2. init hg flow
3. start new feature
4. set branch name containing '#' symbol, e.g. 'id #12'
5. finish feature

Expected result: can finish feature
Actual result: "Feature Name:" field is empty and grayed out, "OK" button is disabled.

The reason is in SourceTree.Repo.RepoHandlerHg.GetFlowList(...) method: regular expression prohibits the use of '#' symbol in the branch name.