version string.

_version_check(): Backport the setting up and checking of the storage
version string.

the tests.

same results regardless of case.

(1) Change the mapping from zLOG levels to logging levels to use
    custom intermediary levels 15 and 5 for BLATHER and TRACE, rather
    than using a confusing skewed mapping.

(2) In the ZConfig datatype definition for a logging level, added
    'blather' and 'trace' to the level names, added 'warning' as an
    alias for 'warn', change 'all' to mean 1, and add 'notset' to mean
    0.  The semantics of NOTSET are very different than those of 1;
    setting a logger's level to NOTSET searches for a parent logger
    with a nonzero level.  The root of all loggers is initialized with
    WARN as its level, so setting the level to NOTSET effectively sets
    it to WARN rather than to the most inclusive level!

(3) In the schema, change the default level for handlers to notset, so
    they use their logger's level; the default level for the logger is
    set to info, corresponding to the old default for
    STUPID_LOG_SEVERITY.

properly, including that use of the these stream names uses a delayed
lookup of the streams).

This implements: http://lists.zope.org/pipermail/zope-coders/20002-November/002680.html

configuration files easier to read.

is piping it to a program that reads logging message from stdin.

types.

bug here, there was a deficiency in zodb_pickle() that will be fixed
in StorageTestBase.py

for both full and minimal bdb storages.

added while a pack was stuck between a mark and a sweep, the mark
would not have found the new objects as root reachable (because they
wouldn't have been stored yet), but the sweep will find then and
erroneously delete them.

_setupDBs(): Add a _packing flag which gets set whenever we're doing a
classic or auto pack

_docommit(): When the _packing flag is set, copy all oids in the _oids
table to the _packmark table, so any objects added between the mark
and sweep phases will not be gc'd.  This is fine because if they're
still not root reachable by the next gc pass, they'll get collected
then.

pack(): Set and reset the _packing flag around the calls to _dopack().

Also, get ZERO from the package, and add the `info' table for storage
metadata.

_docommit(): Fix a reference counting bug caused by not incref'ing the
objects referred to by the new pickle of a new object revision.

added while a pack was stuck between a mark and a sweep, the mark
would not have found the new objects as root reachable (because they
wouldn't have been stored yet), but the sweep will find then and
erroneously delete them.

_setupDBs(): Add a _packing flag which gets set whenever we're doing a
classic or auto pack

_docommit(): When the _packing flag is set, copy all oids in the _oids
table to the _packmark table, so any objects added between the mark
and sweep phases will not be gc'd.  This is fine because if they're
still not root reachable by the next gc pass, they'll get collected
then.

pack(), autopack(): Set and reset the _packing flag around the calls
to _dopack().

Small refactoring and bug caught in computation of "plast" which had the potential to cause slowness.

- make it easier for an admin to configure logging levels
  (by making the defaults more sane)
- refactor the tests a little, in preparation for more tests

- remove methods that aren't needed
- rename "resolved" to "instance" for readability