Add AWS Actors using boto.
Add simplejson to requirements.
Add SQS "wait until empty" Actor
Add ELB-Wait Actor

* UNTESTED
Minor code refactoring

* Create AWS base class (not a base actor)
* Use tornado_sleep() everywhere
Add unit tests for aws.elb actor
Minor tidy up here and there
Major refactor of AWS ELB Actor.
Small improvements to AWS SQS Actor
AWS ELB Actor improvements and tests.
Specify boto version in requirements.txt
Patching ELBConnection to help TravisCI
Revert "Patching ELBConnection to help TravisCI"

This reverts commit 72c3565f7c146bf25a7b36f45a0aa2bcc8834af7.
Change default AWS settings to use empty string.

* Using None instead of an empty string forces boto
  to instantly open a connection instead of creating
  a lazy connection object.
Sort imports and group by native, 3rd party, ours
Add comments/doc to aws.
Delete multiple SQS queues by regex
Merge pull request #6 from Nextdoor/aws_actors

Add AWS Actors using boto. Closes #9