angular/angular.js

- parallelize the tasks
- cache requests (e2e tests)

This reduces the time from ~18min to ~12min.

It makes the output little messy. We could buffer output of each task and display it once it's fully finished, nicely. I think giving instant feedback is better.

This should not affect the Jenkins build at all.

Now, the Travis build uses Chrome on Sauce Labs, which in theory gives us opportunity to use any
browser/platform that Sauce Labs offers.

And also add shared config to make karma configs a bit simpler.