Added DigitalOcean API V2

API V2 Added.

More comments and unit-test should be written.
Added Image listing

Image listing including cache as DO  takes 8seconds to answer.
Fixed capabilities and launch to use proper region

Fix of states
Fix of launchoptions with regionId not specifiedp roperly.

TODO: RegionId filtering in listImages / listRegions since their API
provide data for all regions... and not the currently selected one
Fixed SSH Key

Added SSH Bootstrap Key.
Fixed testContext

Implemented testContext
Renamed models
Added local file caching

In case someone want to prevent the call to digitalocean (which in some
case is usefull as some object might not be available at this time)

Does not cost mmuch to do.
Oops typo
added back cache for product with file
Merge pull request #1 from ACenterAInc/master

Added digitalocean on dasein cloud framework