Arch python binary patch was broken since improvement in 785068df. This
change fixes patch, removing most of the lines thanks to the new PYTHON
variable.
New source file already uploaded on AUR.

Added a README.md to explain the purpose of the directory
Fixed dependencies in PKGBUILD
Added patch to change python binary name for arch users, so they
don't end up using python 3 (python links to python3 by default on arch
linux).