Add visual indicator when a fatal failure occurs

When a fatal failure occurs, a error indicator is added to the status bar, flashes red once, and then turns back to transparent background.

A modal dialog will open when the indicator is clicked, reporting the error, and providing a way to go to the error in the document.

The status bar indicator will go away as soon as Reporter.prototype.checkFatal returns false (no more fatal error).

The formatting and text can probably be worked on, but this is my initial commit for this subject.
The contents of the status bar indicator - is it always a JSHint error? Or could it be a JSLint/ESLint/JSCS/etc. error? If so, what should we change the text to?

I think that having it be `Interactive Linter Fatal Failure is both too long and not true - it isn't the extension that had the failure. One idea I had is to use indicators such as a red X or yellow warning sign for this (which seems like a good idea, since it fits with the default linter symbols).