Add Testcase demonstrating fail on join

When a join is attempted while the transaction is in COMMITFAILED
zope.sqlalchemy is left in an inconsistent state.

See https://github.com/zopefoundation/zope.sqlalchemy/issues/2
Move join to before _SESSION_STATE is set

If the join() errors, _SESSION_STATE does not get
wedged.

fixes https://github.com/zopefoundation/zope.sqlalchemy/issues/2
forgot changelog entry
Prepare zope.sqlalchemy 0.7.3.
Back to development.
Add dist to ignore.
Travis config.
Update bootstrap.py, maybe this will be python 3 compatible.
Need to upgrade setuptools on travis.
Stop createuser prompting.
More defaults for annoying postgres 9.1 createuser
Turns out the user already exists.
Add travis button.
* Add a new function zope.sqlalchemy.register(), which replaces the
  direct use of ZopeTransactionExtension to make use
  of the newer SQLAlchemy event system to establish instrumentation on
  the given Session instance/class/factory.   Requires at least
  SQLAlchemy 0.7.
Merge pull request #4 from zzzeek/master

add new register() function to establish zope listener via SQLAlchemy events
Merge pull request #1 from zopefoundation/master

Merge in latest zone.sqlalchemy