use sbt instead of maven
update versions
added scalariform and reformatted source
fix bin/start and README
Merge pull request #269 from drexin/wip-use-sbt-drexin

use sbt instead of maven
added models for groups and stub GroupsResource
UpgradeManager: interface defined
UpgradeActor: first sketch
DeploymentPlan: deployment steps to execute
UpgradeEvent: add success and failed events
GroupRepository: genesis
small changes
Group: add version
GroupRepository: basic persistence
Group: remove clutter
Group: Rest CRUD operations
Make group persistent
Proto: add definitions to proto
Stepping: rename to Step
Group: implement MarathonState hooks
GroupResource: use  GroupManager to implement the methods
GroupManager: handle state updates and trigger deployments
GroupRepository: copy/paste from AppRepository
added restart call
make restart fail if tasks fail to start
added events and fixed callback for startup
make EventBus mandatory
DeploymentStep: now has waitTime and a check function
DeploymentAction: now has tasks to kill
GroupRepository: load latest AppDefinition from AppRepository, when Group is loaded
ignore local mesos.proto
added DeployActor