Mem tab: tests

This PR adds Jasmine/Karma tests for the membership payment form.

![screen shot 2014-06-26 at 10 42 40](https://cloud.githubusercontent.com/assets/1170410/3397181/750c35ec-fd1a-11e3-845d-6189d391fbe2.png)

The tests run separately from the common tests and as such have their own karma config file.

I'm aware that the loading of the form fixture is done differently from the rest of the tests on NGW - we are due to import that method of fixture loading in to the mem project and at that point I will update these tests.

I've also included some cleanup of the mobile css and css for clients without keyframes support.
We already have this further up the chain in: https://github.com/guardian/frontend/blob/master/common/test/assets/javascripts/setup.js#L5