Add proper 'kingpin' entry point to setup.py.

With this checkin, a real pip install can occur and the user can execute
Kingpin with the 'kingpin' command.
Merge pull request #65 from Nextdoor/proper_entry_point

Add proper 'kingpin' entry point to setup.py.
WIP: Split Terminate and Destroy actors
Fix for 'enable' option in Launch actor.

* Improve logging
Add problem checking before run.

* Move deploy script outside of kingpin (does not rely on pip installation)
* Add find_problems() method which returns a list of problems, or an empty list.
* Modify deploy to check for problems before running code.
* * If any problems are found - run is aborted.

(!) Lacking all sorts of unit tests
Fix and add testing to find_problems method.

* Improve logging
* Fix find_problems for Update actor
* Add find_problems for Terminate actor
Bring test coverage to 100%
Finish Destroy/Terminate split.

* Add unit tests.
* Need integration tests and documentation
Add docs for Terminate and Destroy actors.
Move server array inputs blocking call to API
Make find_problems private and create a public caller
Use mock_tornado for all server array tests.
Run dry before real.
Do different things in dry run to find potential problems
Fix example script names
shorten dry mode log string
Make the DRY statement a prefix for cleaner logs
Simplify finished-log-statement.
Doc string cleanup
Rename SQSRETRYDELAY to SQS_RETRY_DELAY