make evemu Python 3 aware

[Daniel Martin]

Hi,

I just wanted to test evemu(-describe) with my new Logitech tk820 [0]
and noticed that evemu doesn't like to be used with Python 3(.3). So,
I've fixed that ...

First, make testing more easy by being able to change the python binary
via the environment:
[PATCH evemu 01/11] Make it possible to overwrite python binary via env

Python 3 awareness:
[PATCH evemu 02/11] py: Replace print statement with function call
[PATCH evemu 03/11] py: Don't use find_library for libevemu.so
[PATCH evemu 04/11] tests: Replace tab with spaces
[PATCH evemu 05/11] py: Raise exception objects
[PATCH evemu 06/11] py: Fix file opening
[PATCH evemu 07/11] py: Fix file object detection
[PATCH evemu 08/11] py: Add _callstr() - returns str object
[PATCH evemu 09/11] tests: Open temporary device file in text mode
[PATCH evemu 10/11] tests: Fix tests with fixed lists

This one changes the module API, skip it if you don't like it:
[PATCH evemu 11/11] py: Change has_prop() and has_event() to return bool


Comments are welcome,
    Daniel Martin