Option to Cherry Pick the Hotfix Commits

**This pull request contains the following:**
* A new option for `git flow hotfix finish --cherrypick` or `git flow hotfix finish -c`
* Support for `git config` with `gitflow.hotfix.finish.cherrypick`
* Detailed instructions when the cherry pick fails
* Add color support (when supported by the system) for clarity of the output

**Why?**
I do not want to back merge master or the hotfix branch to develop
when I finish the hotfix for many reasons:
* It makes the git log very hard to read and understand
* Removing a feature after a backmerge from maser/hotfix branch is really hard
* If we would like to remove a hotfix commit for some reason it is very difficult after a merge and easy after a cherry pick

Hope you like it.