introduce compatibility with python3

[MichalKrasowski]

fixes #4

Done by launching 2to3 in dvbcss directory.
I have also manually added guard for exceptions module, that is a built-in in python3.

[MichalKrasowski]

Please don't merge yet, some tests are failing.

[matt-hammond-001]

Thanks for doing work on this!

It would be great if the code in the examples directory could also converted to python3 compatibility as part of this branch.

Also it looks like the change to the import queue statement in task.py will break compatibility with python2. It would be preferable for the code to be both python 2 and python 3 compatible.

[MichalKrasowski]

Also it looks like the change to the import queue statement in task.py will break compatibility with python2.

I can see even more problems with my change. It looks like that in my use-case I would also have to update the dvbcss-synctiming repo. I don't know if I will have the time for this.