Make canonical service definition a simple dict.

Since ServiceDef.name now longer exists, it makes it a bit more clear
vs db.DeployedService.name, I think.
Rename Host.foo() method, proper name.
Get rid of post_deploy().

Deployment is now truly service-by-service, no longer file-level.
Improve/spec a proper backend API.
Bring before_start() up to date w/ changes.
Document on_globals_changed().
Be consistent about using the name runcfg.