CIMI: Replaced DataMapper with Sequel ORM
CIMI: Migrated database models to use Sequel
CIMI: Updated CIMI models to use Sequel methods and helpers
Remove index creation errors when database is already created
CIMI: Moved database initialization to models.rb

This will allow proper testing of database
Fixed bugs in storing entity data to database
Added validation to database models
Initial database tests for CIMI frontend
Fixed couple syntax typos in tests and code
Couple fixes to make Sequel run stable on jRuby

- Fixed tests to work with JDBC sqlite memory db
Tests: Replace 'Deltacloud::Database' class with string in DB tests
Tests: Fixed RACK_ENV variable for Travis
Core: Display :destroy_image link only if driver support this operation
Core: Added memory information to hardware_profile label
New driver for digitalocean.com cloud

https://www.digitalocean.com/api
Tests: Set RACK_ENV value to non-empty string (MRI1.8 issue)