Bugfix/help text and reorder rename args

[bmcdonnell]

https://github.com/petervanderdoes/gitflow-avh/commit/c0b4b9673e8fdaf3b250268e002dd4eba145238a and https://github.com/petervanderdoes/gitflow-avh/commit/d6e43fdb37be64af5a3561f63e36b58913e7bc9a add/revise some help text. I think it's a given that you'll want to pull those in, except maybe if you want to change the printout order or something.

https://github.com/petervanderdoes/gitflow-avh/commit/cf3885ed0becd10227da2e997b641deee42a1f36 may be debatable. It flips the order of the rename sub-subcommand arguments to match git conventions--most compellingly, git branch --move [<oldbranch>] <newbranch> (where oldbranch is optional and first). In other cases, "old" isn't optional, but it's still first:

• git mv <source> <destination>
• git diff <oldcommit> [<newcommit>]
• git remote rename <old> <new>

Since rename was just introduced in 1.11.0, less than a year ago, it wasn't fully documented, and error messages should point users in the right direction, would you consider this change is a reasonably small disruption?

[ChrisJStone]

I'm in the process of updating gitflow. If you could kindly resubmit your pull request against my fork here as it appears this fork is no longer being updated.