Basic tests

The easiest possible tests that could import and execute some code. My intent is that: 1) these will serve as a sanity check in a future attempt to port rpctools to Python 3, 2) these will grow over time to become meaningful in their own rite. I went with pytest over nose because I like it better.

I removed the CertValidatingHTTPS class since Eli says it isn't used anywhere and is probably a holdover from pre-Python 2 days.

Some minor documentation updates, typo fixes, and automatic whitespace trimming.