ensure backward compatibilty with multiple python versions

Hi,

After long time (i was also really busy), i come back to you.
I spen time to ensure backward compatibility : different Django version (1.4 to 1.5) and python version : actually 2.6 (my passage on ubuntu 13.04 was difficult to properly compile python 2.6), 2.7 and 3.3. (i'm not sure that versions 3.0/3.1/3.2 are really interesting)
I also try "pypy" but pyzmq crash on build step...

To ensure this, i use the good Tox software, his "tox.ini" config file and a unit test...
It seems very ugly and silly but it's sufficient to "validate" my precedent work on file "instrument.py"...bun

I think units tests on this project can be a good futur practice...
If you're agree, i can create a travis CI file.

Finally, i join a .gitignore "enormous"... i use an arsenal boilerplate (buildout and other) in my Django apps. (tox, coverage, static checker etc.)
 i can understand if you're horrified with this and don't want to include it...