MANIFEST.in: Add tests

[jayvdb]

Closes #32

[ryanhiebert]

Thanks, I need to drop 3.3 to make travis happy.

I'm curious about your thoughts on a similar matter. In my application code, I prefer to colocate my unit tests, which I learned to do writing react/just, and I really like. It feels wrong to have unit tests in the distributed package, though, because they aren't part of the interface I'm publishing.

I know that some distributors require tests in at least the sdist, but that seems like it's limited to source distributions, not wheels. Do you think having tests included in the wheels is good? Collating tests is good IMO, but I don't know how to get them out of the wheel if I do. Not that any of this applies to this package, it just got my mind wondering

[ryanhiebert]

I fixed the tests without dropping support for any tested versions. Sweet.

[jayvdb]

@ryanhiebert , moving this over to moremoban/pypi-mobans#78 , which is a cookie-cutter-like system I've been working on. The recipe we come up with would be re-usable anywhere, i.e. without moban.