Allow disabling DroidDoc build.

Change-Id: Ia842827a46b107bcef0d176deb0ab651e04bfa04
envsetup: export ANDROID_BUILD_TOP earlier

Change-Id: Ia3497f61f4e9aaeeb793cecd3b4f488f0a48181a
Merge pull request #1 from CarbonDev/jb2

Merge CarbonDev