Fix "Maximum call stack size exceeded" error.

Due to conflicting webdrivers (previously we import webdriver and configure it
and protractor does too).

See https://github.com/angular/protractor/issues/360 for the reference fix.
Added support for configuring seleniumUrl. Can be used in combo with a grunt task that starts the selenium server for you automatically.
Merge pull request #8 from nowells/master

Fix "Maximum call stack size exceeded" error.