Re-enable tests for phantomjs

[jasonsanjose]

Pull #3101 disables LanguageManager-test and PreferencesManager-test due to a new dependency on shell APIs in brackets.app.

We should re-enable these tests by properly mocking the shell APIs...something we would have eventually done, but have not allocated time or written a story for yet. What this buys us is the ability to run more tests in a headless environment on Travis-CI or locally via grunt.

[pthiess]

Move to Backlog

[njx]

@jasonsanjose - seems like if we want to pursue the phantomjs-based tests further, we'd really need a user story-level amount of work. Do you think that's valuable to pursue anytime soon?

[njx]

(If so, go ahead and add a card to the icebox, and either way you can close this out.)

[jasonsanjose]

Can we lump this in with https://trello.com/c/wbdr7KxI or https://trello.com/c/rY8IdSd6

[gruehle]

Added to https://trello.com/c/rY8IdSd6

Closing