Add doc strings and documentation

[jettify]

No description provided.

[n0mn0m]

Any specific areas you think should be targeted first? I know the examples are there do you think connection.py, pool.py or something else would be good to start working through and documenting? Or would it be better to focus on functionality documentation?

[jettify]

Any place you like or enjoy doing, we are grateful full for any help.

For end users of library I think Getting Started section is most valuable part as well as docs for core API (cursor, connections, pool), doc strings are a bit less usable.