Failing steps for: when run with no license or --license "NONE", "LICENSE.txt" should not
exist

Currently, the file still gets created by `bundle gem` and contains the
MIT license.

Also move the slowest scenarios to the end in features/license.feature
to the end of the file.
Remove LICENSE.txt when run with no license specified or with --license NONE
Failing step for: the gemspec should mention the correct license
Make the gemspec use the correct license
Failing test for: The whole initial state of the app has been staged with git
Stage the whole initial stage of the app with git
Merge branch 'feature/git_add'