build: add support for custom releasetools

Change-Id: I2337559ac669bb5868708c4726cbacbf5713261a

Conflicts:
	core/Makefile
releasetools: support more partitions and different fstab types

* add BML support for Samsung legacy devices
* add ext2, ext3 and vfat, f2fs support for EMMC
* fix recovery.fstab for ADV recovery

Change-Id: I6b76d2a21fe68096cf1b0cd850cdfb3a313370d1
envsetup: Set CUSTOM_BUILD environment variable

This is used to gate a few features, including backuptool

Change-Id: I02fee9e0765cca88c833bb0514762aa3b14642e3
envsetup: add a helper to fix "out/target/common" not being really common

* out/target/common isn't really common, and if you do
  back to back builds for multiple devices, that is noticable.
* Use out/target/common-$device instead, and link the appropriate
  dir to out/target/common every time lunch() is run, if
  ANDROID_FIXUP_COMMON_OUT is set.
* Refer https://groups.google.com/forum/#!topic/android-building/ispbOgzoyg8
  for more info.

Change-Id: I11e7df0e68e2a60ce32576f06397d60fc9465b60
build: no longer build emulator by default

This is just increasing build times when most people are not using it.
Let's speed up builds a bit.

Building emulator should still be possible by appending BUILD_EMULATOR=true
to the build command

PS2: Let's keep the darwin warning.

Change-Id: Ibd8e2b90455bd603a691c7b95466068b6fae212a
Signed-off-by: Andrew Warfield <hiasant@gmail.com>
Always rebuild build.prop file

build.prop file was not rebuilt after changes to $(PRODUCT_PROPERTY_OVERRIDES)
Without this patch, if change I681fd92e will be merged,
the wrong date will be always in the zip file's name
(date of building build.prop and not the current date).
This patch simply forces rebuilding build.prop every time.

Change-Id: I5071072cdbb34865e32403a2e7ce0f705ff9daee
Update to MintKat.

Conflicts:
	tools/buildinfo.sh