Update tutorial docs to use Karma instead of Testacular.

Replaced instances of 'Testacular' with 'Karma' to reflect name change of test runner.
Replaced instances of 'testacular' with 'karma' to reflect name change of test runner.

Replaced instances of 'http://vojtajina.github.com/testacular' with 'http://karma-runner.github.io/' to reflect dedicated page for Karma Test Runner.

Added location of config file needed to start the Karma server in step 2. This is still labeled 'testacular.conf.js' and needs file name to be updated in the phone example repo.