Rename 'otapackage' zip file
build: Add bacon target, and mka/brunch/breakfast aliases

Conflicts:
	core/Makefile
envsetup: Set CUSTOM_BUILD environment variable

This is used to gate a few features, including backuptool

Change-Id: I02fee9e0765cca88c833bb0514762aa3b14642e3
brunch: Rename to AOSP