Make the local tests use "normal" unittest conventions.

Tim pointed out that loadEx is supposed to return a 3-tuple.  This is related to collector 1828 which was already marked as resolved.

The caller can't deal with using current data from loadBefore, so having an "end_tid" of None is useless.

Allow tempstorage to participate in MVCC.  Also fix minor bug where conflict cache could be poisoned by a transaction that failed after store was called.

      - Collector #1655: fixed severe memory leak in TemporaryStorage

  - replaced old CVS expansion with a clean $Id$
  - set the svn:keywords property to "Id"

When you check-in files in the future and want $Id$ to be expanded,
make sure it reads "$Id$" in that file; then set svn:keywords to "Id".

ZODB, ZEO, Persistence and similar packages were not modified since they
are really maintained elsewhere. Right now, we use a copy of them in our
Zope/Zope3 trees. We should go back to the module sharing (using
svn:externals).