controllers: forward pullrequests.delete_comment to changeset Remove duplication between pullrequests and changeset. We move the code outside ChangesetController to make it callable from PullrequestsController. Note: - instead of keeping the method pullrequests.delete_comment itself and letting it forward to changeset.delete_comment, an alternative solution would have been to change the routing table directly. However, the chosen solution makes it more explicit which operations are supported on each controller.

# requirements.txt file for use as "pip install -r requirements.txt" as a
# readthedocs compatible alternative to "pip install -e ." which is a working
# alternative to "setup.py develop" which doesn't work with Mercurial 3.7
.