Merge pull request #273 from sethmcl/master

Printing process stdout for Phantomjs in debug mode
Updating package.json and CHANGELOG.md for 2.1.4 release
Improve exception handling and reporting of test errors (failures to run tests)

* Reject promises with proper error objects
* GhostDriverUac will now try to kill other instances of phantomjs before starting, to increase reliability.
Merge pull request #274 from sethmcl/catch_exceptions

Improve exception handling and reporting of test errors (failures to run)