Add Debian build dependencies

Debian Jessie has slightly different package names than Ubuntu.
Create gpl-2.0.txt
Create gpl-3.0.txt
Update README.md

Add installation docu via AUR
Merge pull request #31 from JIghtuse/master

Add Debian build dependencies to README.md
Merge pull request #34 from bh/master

Added Arch AUR install instructions to README.md
Merge pull request #32 from viljoviitanen/add-licence-files

Add licence files