angular/angular.js

Setting env var `BROWSER_PROVIDER` to `browserstack` or `saucelabs`
determines which browser provider will be used.

This does not affect the build as all jobs are set to use SauceLabs.

Switch to Karma with Socket.io 1.x, which solves some issues(*) with BS.
Thus removing `config.transports` as it is not used anymore
(Socket.io 1.x starts with polling and tries to upgrade if available).

(*) folks from BS were fiddling with socket.io configuration to get it stable.
See dhimil/karma@4c04011
This is not necessary with Socket.io 1.x.

… for loading pages

This should help with occasional safari page load timeouts. In a test of
4500 page loads, the current 10 second limit caused 3 errors while a 30 second limit
caused none.

Closes #8231

Because of this[1] issue, which is Linux specific, we see very frequent failures.

[1]: https://code.google.com/p/chromedriver/issues/detail?id=467

See 28ef263

FirefoxDriver seems to have an issue with FF29 which is breaking a test case, and causing false negatives.

There is an issue opened on protractor regarding this at angular/protractor#784

Closes #7369

… of by browser

Use the multiConfiguration ability of Protractor to start tests on multiple browsers
from the same travis cell. Group tests by type (jquery, jqlite, or docs tests) instead
of by browser. Turn on tests for jQuery.