Add ability to pass job annotation params to Saucelabs

Saucelabs allows you to pass in job annotation parameters for session `name`, `build`, and `tags`. See screenshot below:
![screen shot 2014-03-12 at 3 25 36 pm](https://f.cloud.github.com/assets/1276103/2401988/97b8a054-aa1c-11e3-920b-ea66cbc23053.png)

You can pass in these values to selenium as described here: https://saucelabs.com/docs/additional-config#metadata

We're running tests on Saucelabs at work, and it would be nice to have this functionality available via `grunt-mocha-protractor`. I manually verified that it correctly passes these values to Saucelabs. The screenshot above was from the manual verification.

Thanks for your work with grunt-mocha-protractor, Andrew!