test_ruok was hanging under Python3. Now it doesn't hang but just fails with 'struct.error: unpack requires a bytes object of length 4'

Fix some test failures under Python3.3+. This loop can also raise a RuntimeError([Errno 9] Bad file descriptor), though, so not all are fixed. But this may be enough to fix the hang.

Try to remove use of virtualenv in .travis.yml; all the travis builds were running under Python 2.7.3 because of it.

Make the virtualenv python report its version; seeing /usr/lib/python2.7 in the python2.6 traceback paths is making me nervous.

- make the locked decorator easier to inline by not creating a new closure every time.
- use builtin dicts instead of the pure-python BTrees (only under pypy)

"Transaction",                  AFTER    BEFORE
"Add 3000 Objects",             10014      8777
"Update 3000 Objects",          12199      8805
"Read 3000 Warm Objects",        4294      3699
"Read 3000 Cold Objects",        4264      3676
"Read 3000 Hot Objects",        79764     58732
"Read 3000 Steamin' Objects", 2667283   2574508

Rollback some test changes now that Python persistent handles registration during __setstate__ the same way C persistent does.

After study, the delayed release of iterators under PyPy seems harmless. Move the gc calls that clear them to the test case.

Get status information via the zeo port and a nagios monitor

So we don't have to worry about incomplete sends or recvs.

the ZEO port without creating a full-blown client connection and
without logging in the server log.

- Support new Python versions.

[ci skip]

Before Python 3.4, the logging module registered them in both
directions, but quit doing so in 3.4, breaking doctests which expected
to display custom level name ("BLATHER").

See: http://blog.travis-ci.com/2014-12-17-faster-builds-with-container-based-infrastructure/

Add server side logging for MTDelay

Log level INFO

20 minutes to read the code in order to find where to set the log level :) 
Hope to help other people ;)