Increase reliability around connection failures

There are a ton of different areas where I've worked to increase connection reliability.

  1. Removed our custom thread_coroutine() decorator and instead use the tornado.concurrent.run_on_executor() decorator. It does the same thing, but its more well supported.
  2. Built in custom Exception logging for thread-wrapped methods.
  3. Bump Tornado to 3.2.2 to solve random Threadpool IOErrors, and use per-package Threadpool objects for `actors.aws.sqs`, `actors.aws.elb` and `actors.rightscale.api`.

The big improvement though is actually https://github.com/brantai/python-rightscale/pull/8. Disabling keepalives seems to have greatly increased our reliability when doing lots of API polling.