Nicer handling of resizing with respect to screen boundaries

[jakereps]

Currently the default behavior of expanding an Electron BrowserWindow is just to expand it outwards from the top left corner (i.e. in the positive x and y direction), but that doesn't play nicely when the screen is nested in any corner other than the top left corner, as growing in that direction pushes it off the screen.

This should be handled using the screen module of Electron. I think the way to do it would just be to force it to stay on the screen by also dynamically manipulating the x, y values on resize.

Another way could be to limit it to only be able to be placed in the corners and expand outwards from them, but that seems a little restrictive.

Bounds contraints:

_ _ _ _
|      ↑|
|      _|
|  ←  |_|
|_______|

Corner pinning:

 _ _ _ _              _ _ _ _
|_|  →   |    and    |  ←  |_|
|_↓______|           |_____↓_|