Formatting: conform to jshint style guidelines

The code I wrote to set div#diva-outer's left margin was not using the ternary operator for an assignment or function call, which is apparently bad practice. I've refactored my code to use the ternary operator for an assignment, and it's more readable.
Fixed: resizing window in fullscreen and switching back to regular view didn't update diva-outer width

Now, at the end of handleModeChange(), we update the width of the document viewer if exiting fullscreen.

Fixes #139
Formatting: settings.inFullScreen does not exist

Lowercased the setting name to match the actual setting. This might have caused problems with subscriptions to the ModeHasChanged event (though nothing is hooked into it by default so far.)