Added gevent and greenlet in requirements.txt.
Added methods for integration with gevent sockets.

Sockets will be used for the external interface signals.
import daemon as daemonizer since the name of our Python module is already daemon.
Package clean-up. But not yet as clean as I'd like.

Renamed daemon.py to sfdaemon.py to resolve namespacing issues. For some weird
reason, doing `python setup.py install` still adds deleted files (pytheas.py,
daemon.py) to site-packages/pytheas.
Added logging statements for debugging weird bug where daemon shuts down abruptly.
Added more logging statements. Figured out the problem with abruptly terminating daemon.

It seems that python-daemon is not compatible with gevent. In the main daemon
function, changing the call from `gevent.sleep` back to `time.sleep` fixes
everything back to normal.
Updating manifest.
Rollback fixes to classes. Problems as described below.

- python-daemon is not compatible with gevent.
(see also 26b26fa1bc56bd66c7b8fc01715bf84d1e3ffb5f)

- Weird behavior where the logging in redis_patterns.RedisSender is raised in
redis-py's classes. Not sure if this is a bug with redis-py, with redis, or
with my logging set-up.
Modified CHANGES.txt.