Change Hotkey and Fixed Auth

It's been a while. There's still only 40 active users of SpotifyKeep but I figured why not go ahead and fix things up. The much requested and long awaited feature to change the hotkey has arrived. Additionally, some errors during authentication have been fixed as well.

Album images now work on Windows :D

And a huge speedup on Mac!

Thanks to a new beta version of Electron that includes working Notifications on Windows, we can now show the album cover image for whatever song was saved!

I also added a flag that disables chrome sleeping in the background, which never effected Windows but caused Mac to take upwards of 30 seconds to save a song. That's now fixed.

First release!

Yay!