is 7.4 required for python support?

Thanks for this great package! I am able to use it just fine locally (where I have vim 7.4), but I'm getting terse `(2/4) [EXECUTE] (X) Vim(python):Traceback (most recent call last):` messages on the any steps that involve Python when I try to run in on TravisCI.

From #6 and my own experience, it seems like the pure-vim tests run fine under the vim that's available by default on Travis, but I see that in your own `.travis.yml`, you build Vim from mercurial source. Do you know what minimal set of features Vim need to be compiled against in order for Vader to use Python support?