Display current project name in main window

Supersedes #6878.

This implements #2281, displaying the project name in the Brackets window title.
Argh! All of the unnecessary whitespace changes in this file (and others) are making my life difficult. I'm trying to keep my [promises-upgrade branch](https://github.com/adobe/brackets/tree/promises-upgrade) up-to-date and every one of these whitespace changes that coincide with any change in my branch causes a phantom merge conflict that needs to manually resolved. Please stop doing this! Brackets has no convention for whitespace in empty lines -- it's left to the authors discretion to have none or match indent level of previous/next line of code, so there's nothing to "fix".

Sorry @le717 I don't mean to single you out -- I'm just using your code as an example. This comment is meant for *everyone*: contributors and committers.