Try testing using different installation schemes.
For some reason, --version does not emit the same string as ends up in the artifact filename.

Do an awful hack that's probably broken in the general case.
Surprise!  Just kidding!  sdist and bdist_wheel are totally different.
Spill your guts travis.
Only Python 2.7 please.  Also without this the guessed filename is wrong.
Remove the debug echo.  Add some comments.
Merge pull request #39 from exarkun/test-installation-34

Test different kinds of installation.