roomservice: add remote support, better deps

Devs can now declare a remote in carbon.dependencies
deps are now handled better, too. Remote and
revision are now honnored.

Change-Id: I429c164b9d81fb3f4d06f479c13be1927126552b
Signed-off-by: Simon Sickle <simon@simonsickle.com>
Merge "roomservice: add remote support, better deps" into lollipop