These services can now be excluded by modifying the list of REQUIRED_SERVICES (TB renamed)
Changed appwidget, devicepolicy, backup and print services.
Change-Id: Id8e2855d5c045cd57bdb02dca9ed75172803bce7
Refactored the directory structure so that services can be optionally
excluded. This is step 1. Will be followed by another change that makes
it possible to remove services from the build.
Change-Id: Ideacedfd34b5e213217ad3ff4ebb21c4a8e73f85