Add initial approach to put Django's asserts into pytest's namespace. #97

It's only draft version.
Better write this as `from ... import ( ... )`.

See https://github.com/timothycrosley/isort for a nice tool to sort imports automatically.

I use the following command with Vim:

    command! -range=% Isort :<line1>,<line2>! isort -

/cc @pelme