Built-in skins / colorschemes aren't applied #143

The app doesn't recognize any built-in skins. It doesn't throw any errors, but no theme is applied unless you create a ~/.config/gonzo/skin directory and place a skin file there.

I assume this is either a bug, or the built-in themes aren't actually built in. If not, README.md and SKINS.md should be updated.

Gonzo version: v0.4.2