tornado's ioloop intergration

Sample usage:

from pyxmpp2.mainloop.tornado import TornadoMainLoop
Client(jid, [self, version_provider], settings, main_loop=TornadoMainLoop())
add docstrings and fix some warnings by pylint
fix a bug caused by previous cleanup
Merge pull request #76 from lilydjwg/tornado_mainloop

tornado's ioloop intergration
'py3lint' make target added

This allows to run pylint via python3 on Python 3 code.
Trailing white-space removed
Catch IOError raised by getaddrinfo()

getaddrinfo sometimes raises random IOError exceptions when
a name cannot be resolved (Python or stdlib bug?). Catch it like
the 'socket.gaierror' exceptions.

This fixes the TestDumbBlockingResolver test for me.
README: added warning about current code status
setup: use distribute only if installed
Merge pull request #81 from hensing/master

setup: use distribute only if installed
Merge pull request #82 from lovesnow/master

Fix ThreadPool._remove_timeout_handler() method