Merge from product_installation_tracking branch. The product install now keeps a dict of installed products, and ZopeTestCase checks it, so not to install products twice.

- added some basic conformance tests

Note that this is just a first step:
- there are still some z2 interfaces that are not bridged to z3 interfaces
- the bridging introduces a dependency on Five, non-dynamic z3 interfaces might be more suitable (but add redundant code)
- 'implements' declarations are not complete
- many interfaces have unresolved XXX coments

Added test for strftime with unicode pattern.

      - Collector #1323: applied patch to fix umask problem in zdctl

Use ZODB 3.4b3.

Stop using deprecated txn_mgr= argument; use
transaction_manager= instead.  Stop "illegal" use of
Connection's private ._txn_mgr attribute; use the new
public .transaction_manager attribute instead.

- Note about the change

- Make it so webdav-source server is distinguishable from the default http server in the ZMI and event.log

inet-address default, which does not make a lot of sense for binding

      - Collector #1780: DateTime.strftime() now handles dates <= 1900 or
        >= 2038

without touching sys.path and without the help of imp.

something went wrong during execution of 'function'.

- docstring cleanup
- whitespace cleanup
- import cleanup

(Thanks to Dale Hirt for the patch).

and pushed reponsibility for closing the REQUEST down to the registry.

The Finder class is now used for the complete lib/python tree and has a blacklist instead of a whitelist for file extensions.
So there should no longer be a need to update setup.py if modules or files are added or removed in lib/python.
http://www.zope.org/Collectors/Zope/1776