Add Emacs theme

[superuser-does]

Not a distro but the most important piece of software for some of us!

There are about 3-4 official Emacs logos because of the long history and chaotic nature of Emacs. However, I'd suggest one similar to the E at the top of the project website which is also the icon of the program.

The official gradient version is here but I know that's not in the style of your themes. There are 'flat' versions of this E logo available in numerous icon packs for Linux but I couldn't immediately find a good one, apologies.