PEP8-compliant HDFStore documentation
(This is to be applied after a PR from https://github.com/jreback/pandas/tree/pytables_update7, as it is based on it)

This is my first PR and I am hoping to get right the github worfklow to start with 'real contibutions'. Any hints on how to PR better very welcome.

@jreback when you get a chance can you skim the changes to the docs here?
 I think this is fine to merge in as is (with usual fixes to change 0.10.2 -> 0.11 for RELEASE and whatsnew)
 cherry-picked @meteore's commits
