Specify maxsize to QueueTask.queue

This can be used as a way to "throttle" throughput. Producers can either
block put on the queue (and pass the backpressure upstream) or
put_nowait and handle the backpressure some other way.
Update to standard FB BSD + Patents License
FacebookDbusService -> FB303DbusService
Add compat module for py3k compatibility
py3k-compatible metaclass declarations
Use print_function from __future__ where possible
Skip deferred queue task test if twisted is not installed
py3k xrange compatibility
Remove unittest2 unit test dependency.

Newer versions of python have a good enough builtin `unittest` module,
and unittest2 is not py3k-compatible.
py3k Queue -> queue compatibility
py3k unittest compatibility re: PEP-420

Python 3.3 adopted PEP-420.  This means that the thrift/ directory in
the repository root was getting imported in this unittest, and the task
was not getting skipped properly.

More specifically import the thrift.server module, so we don't
incorrectly allow this test to run in py3.3+
Update classifiers to enable py3k compatiblity.

Also, enable travis builds

Note: Sparts is currently only minimally supported on py3k.
Many of its features are dependant on other libraries that are not yet
supported.
Use new-style octal literals for py3k comaptibility

e.g., 0oXXX instead of 0XXX
Tornado py3k compatibility
version-specific travis requirements
irc notifications for travis