Squash chromium prebuilt feature (1/2)

Credits to OmniROM and PA

build: Add chromium prebuilt support to envsetup.sh && The core Makefile

This adds a chromium_prebuilt function to envsetup.sh that is invoked by lunch to check
whether the chromium prebuilts are up-to-date or not. If not, it will be built from source
and then the new source built version will be pulled during brunch/mka bacon to become the
new prebuilts for future builds.

This is all opt-in through the USE_PREBUILT_CHROMIUM flag. Without it being set to 1,
none of this would be ran, and regular operations will go on.

PS13:
-use export TARGET_DEVICE
-replace git -C with params compatible to old git versions

Change-Id: I40f8c8dbd2a8a84a5c1b9f47ee04180a71ef4e07

Conflicts:
	core/Makefile
	envsetup.sh

build: Fix PreBuilt Chromium refs

Change-Id: Icc553d5be1e71d8c754bc85b6906252e5690b508

Conflicts:
	envsetup.sh
Keep InCallUI in memory (3/3)

Build the dummy InCallUI apk

Change-Id: Icb82e8c3b7bedb5deb1e7adc779cd4bd8dbc3b72
Finisher script (1/2)

Change-Id: I32258afd40ac5ea867b065a99d3045129ffab07c