Cleanup and refactor digitalocean integration

* Handle case where droplet is locked pending events, DO support says
they are planning to expose something in the api to show these events.
Until then this is the best we have.
* Whitespace cleanup
* Refactor test helpers
* Use the collection helper for the digitalocean servers collection
Whitespace
Whitespace, fix tests for running in non mock mode, and clean up in non mock mode
digitalocean supports bootstrap
Fix digitalocean server test
Add digitalocean mock key to run these tests on travis
Add ip_address to the mock
Remove mock server from servers list on destroy
Add ip_address method back, but deprecate it.
Merge pull request #1971 from trobrock/better-digitalocean

Better digitalocean support