Added Moka Icon, GTK and Gnome Shell repositories and installer for Fedora 18, 19 and 20

Moka is a modern open-source design project with a goal of bringing a high quality visual experience to many platforms.

More info at : http://mokaproject.com/
Removed Moka Gnome Shell theme & fixed Moka themes repo name

Also added me in the CREDITS file.

More info at : https://github.com/Pulgafree/fedy/commit/e157fa98b46936d2a838825b0a383e1b2341cb74#commitcomment-5390635
Merge pull request #77 from Pulgafree/master

Added Moka GTK and Icon Theme