Passes --save-diff flag during record

Useful for debugging WebDriver / Selenium flakiness that prevents the
pixel-perfect automation check from succeeding.
Includes a 'browser' command line flag
Better key coding

Special cases the non-Unicode key codes that JS generates in key
events. Also switches to key down to get more reliable "shiftKey"
information.
Better tolerance of missing screenshots
Fake screenshot to solve Chrome
Correct size to be the viewport not the window
PhantomJS support with Chrome as interactive browser
Adds support for a mask (good for iOS)
Quit rather than close to clean up grid sessions
Correct comma-separated name list
iOS driver support
Support for home / end keys

Also doesn't blow up if click doesn't match Safari element
Merge pull request #1 from crashlytics/patch/home-end

Support for home / end keys
Re-use the remote session to speed up iOS runs
Merge pull request #2 from crashlytics/reuse-sessions

Re-use the remote session to speed up iOS runs
Merge branch 'master' of github.com:crashlytics/huxley

Conflicts:
	huxley/run.py