improve issue reference and time tracking in commit messages

The documentation of git commits (https://git-scm.com/docs/git-commit#_discussion) suggests that

Though not required, it’s a good idea to begin the commit message with a single short (less than 50 character) line summarizing the change, followed by a blank line and then a more thorough description. The text up to the first blank line in a commit message is treated as the commit title, and that title is used throughout Git.

Using this short/long terminology of a commit message -- currently gitlab only supports referencing issues if they are in the "short" portion of the message. This is quite ugly and cluttering to the message history. GitLab should scrape the full commit message and allow support for referencing issues in the "long" part of a commit message, so as to keep these unsightly references off the neat short log.

Furthermore, we should be able to add time spent and estimated to the commit messages. Frequently someone might open an issue for us but we don't actually have an estimate until we start getting to work on the code starting to make commits. Also we might just want to add time to something, or many things, that we are doing. Thus... it would be super useful to make longer commit messages and have gitlab support the references like the following example commits

Begin buildout of feature

gitlab-ce#25 /estimate 1d /spend 1h

Continue to develop featureX and fix bug causing problemY

gitlab-ce#25 /spend 2h

fixes gitlab-ce#4 /spend 30m