Clear Connection.transaction_manager on close. Fixes #114

Call _p_resolveConflict() even if a conflicting change doesn't change the state

Merge zodbdocs

Don't raise an AttributeError when DemoStorage successfully stores a blob first.

Includes a (previously) failing test case.

Fixes #103.

But we can make it better.

- can ``make html`` from doc directory and get html.

- documentation tests run as part of normal tests.

README.rst needs some love.

Then on to making this work with RTD.

Setup and reference

Reference docs

and fix a ReST issue.

Also the details aren't important here, so moved to a footnote.

Still need to discuss zconfig