chore(tests): Use Karma instead of testling

The testling CI infrastructure is fragile and cannot be relied upon.
We should switch to Karma and then to SauceLabs for our web tests.

The default Grunt task will now run web tests in PhantomJS.
Remove testling configuration

Fixes #3
Added travis saucelabs info
Merge branch 'web-tests' of https://github.com/bripkens/reflux into bripkens-web-tests
Merge branch 'bripkens-web-tests'