Frameless window on MacOS

[egardner]

Electron supports a few different methods for running an app without the gray menu bar on MacOS (apparently this works on some Linux distros as well).

In my opinion this goes a long way towards making the app feel "native". Compare this (default navbar):

To this (no navbar):

Of course, the UI elements in the top left start to collide and will need to be adjusted for this approach:

I'm going to explore some design solutions for this problem in the ui-improvements branch, and if folks like the results I'll merge into master.