WIP: Adding Python 3 support

[shazow]

Hi there, I took a quick attempt at making batterym work on Python 3.

It's not quite done but hopefully this progress is helpful to you. I need to move on to other things for now.

Some things that might still need tweaking:

• AppIndicator doesn't support Python 3, need a backport or something. I have something half-written but never got it working.
• Tests don't run in the current setup.
• I believe setup.py is incorrect, might need to be redone from scratch so that batterym behaves like a proper Python package.

[arch-user-france1]

It is very easy to fix. You have to execute following commands:

2to3 -w *
2to3 -w */* 
2to3 -w */*/*
2to3 -w */*/*/*

Then is should work. It's important to replace python2 with python3 in .sh files.