Module docstring titles should end with '.'

[tovrstra]

This causes a lot of warnings in the QA scripts. Easily fixed.

[tovrstra]

We should also update the script that generates the API documentation to remove this dot from the the RestructuredText sections that are generated from the first line of each module docstring.

[tovrstra]

I'm moving this to 2.2.0 because this is a change that touches every test file. That makes merging of existing branches harder, which we'd like to do in 2.1.0.