Add docs for running tests; fix reqs

This gets everything working to run tests using:

    python manage.py test

This moves requirements up a directory where they're easier to find
for people looking at the source code.

This combines "tests.txt" and "dev.txt". Developers should be running
tests, so it's easier to just have all the bits in that one requirements
file. This simplifies setting everytihng up for hacking.

Documents how to set everything up and run the tests in the docs. I also
added a note about the IRC channel.

I also tweaked .gitignore to ignore some additional things.

I deleted runtests.py and some of the other test scaffolding because
there was too many test scaffolding things that seemed to conflict.
There should be only one true documented way!
Fix AssertionError; signal receivers must have **kwargs

This was causing all the tests to fail under Django 1.4.6.
Fix .travis.yml