FIx Safari tests in Selenium on Travis CI

[jasonmunro]

Safari in Browserstack is a bit temperamental. Most of the issues are resolved, need to figure out the rest and enable in Travis builds

[jasonmunro]

I have enabled Safari tests in Travis/Browserstack, but the situation is pretty bleak.

• Using Browserstack from my local dev environment, 5 tests fail. Same tests every time, which is promising since I can probably code work arounds
• Using Browserstack from Travis, tons of test fail for various reason. Many fail because I can't get the browser window to maximize from Travis, which works from my local environment. Likely this is due to a version difference between the two environments somewhere (selenium?).
• For all other browsers, we exit on error if a Selenium test fails, but for now we don't for Safari. This way we still get notified if tests expected to pass fail, but I can keep Safari running in Travis while I work on figuring out solutions.