defaults to the present and a 'days' keyword argument can be used to
specify a number of days pervious to the time to pack to.

A wait keyword argment can be provided for pack that causes the client
to wait for a pack response from the server. NOTE: no other requests
will be sent to the server while waiting for the pack response. This
feature should only be used from utility packing scripts.

Got rid of the no-longer-used (synchronous) store method.

Added a wait argument to pack.  If the wait argument is provided,
then the pack method doesn't return a value till packing is done.

Simplified the way errors are handled in normal calls and
packs by putting the error marshalling logic into a separate
method.

No longer log UndoError, VersionCommitError, and TransactionError
exceptions on the server, since these are user-level errors.

Do log pack errors.

defaults to the present and a 'days' keyword argument can be used to
specify a number of days pervious to the time to pack to.

Rearranged handlers to make them a little less signal dependent.

"address already in use" errors.

editorial changes.

files if no directory was specified in the var directory and if
INSTANCE_HOME isn't set.

between calls from the storage and from the out-of-band
invalidation message handler.

on start up, with the default being to wait for the server.

The intent was that it should be possible to bring a client up even
if it can't talk to the server, however, this is a little bit risky if
we need to start them both.  Eventually, we need to be the start-up
code be smart enough to wait if we can't serve data requests during
startup, but to proceed if we can.

a memory leak in mounted databases.

This was to fix a bug caused by an interaction with ZEO that caused a
process to be unable to start if the ZEO client cache contained stale
data.

getting the local and global transaction locks. This has a disastrous
effect, causing updates to be missed locally and causing the
transaction id to be lost.

raise an exception. It should catch and serialize exceptions raised by
the underlying storage, however, unpicklable exceptions could cause it
to accidentally raise an exception. We now pickle exceptions more
carefully, catching and handling pickling errors.

  - Close sockets on process shutdown. This should avoid "address
    already in use" messages on restarts.

  - Log shutdown.

Fixed bugs in handling -u option:

  - The -u option wasn't registered with getopt

  - User lookup failures weren't logged correctly.

Send storage size info to all clients at end of pack and
commit.

understandable.

Sped up startup a tiny bit by not doing synchronous get_info call on
startup. Instead, server will send info asynchrously on startup.

to avoid a security problem arising from the way that Zope
changes the effective user id. The first cache file gets created while
Zope is root, so it can't be reopened as nobody.