Build: Add support for specifying build variant in brunch/breakfast

This little modification allows specifying build variant in brunch/
breakfast commands. For example we can use "brunch i9300 user" to build
user variant instead of default userdebug.

When no extra argument is given, userdebug is default.

Change-Id: I935327252098ee74b34a815a023d2ac6b9a53a30
build: qcom: Set QCOM_*_PATH variables for hardware/qcom-* projects

This consolidates a bunch of one-off logic scattered throughout the
code base.  Usage in Android.mk files is trivial:

At top level, use e.g. "ifeq ($(call my-dir),$(QCOM_AUDIO_PATH))".
This works for all variants, including non-variants (i.e. AOSP).

Within subdirs, use e.g. hardware/qcom/audio => $(QCOM_AUDIO_PATH)

Change-Id: Iee2497ea9a7efeb4ae9e861b84c532b19da7b69d
Merge branch 'kk' of git://github.com/CarbonDev/android_build into archi-ckk