Tartarus support AND "No devices" mode added

Ever wondered what happens when you open razerCommander and nothing happens? Probably no device is detected. Instead of just printing it in the terminal, it's now shown in the GUI.
Also, started working on an Update button for connecting new devices on the fly.
Finally I added initial support for the Razer Tartarus, for anyone out there owning one.

Before installing razerCommander

Install the driver for razer devices from this repo. After you're done follow the instructions for your distro down here.

Ubuntu and Debian

Download the deb from this page.

Arch

Install razercommander-git from AUR.

Other distros

Clone this repo and run main.py manually, if you have GTK 3.18+ it will work fine.