Ignore LOCAL_AAPT_INCLUDE_ALL_RESOURCES on mdpi & ldpi devices

Ensures that certain packages don't include unneeded hdpi or higher
assets.

Change-Id: I8e62486f21382e21ec8a587ce96b2383761aad3a
Disable art & chromium properly

Change-Id: I7c29d26f9b022c38fac051ded8f654dac29bc6ee
fix renderscript on armv6

Change-Id: I785a97ff8976896f99ff4725a7ccba133876c3d8
build: copy extras_file path

Change-Id: I078d3efcf4da764e8671c7eebdf5fe35c2794f7f
build: add proper extras_file support
Allow MINIGZIP override for default ramdisk compression tool

The Android build system only supports gzip for ramdisks, despite
the kernel itself supporting other options. Allow per-device
configs to specify their own tool, like so:

MINIGZIP := $(shell which lzma)
MINIGZIP := $(shell which bzip2)
...etc.

Change-Id: I0bc754bd2a73bfb4166228b420c8f013808c82f2
Enhance support for custom compression

Ensure that custom MINIGZIP tool does not cause issues elsewhere
in the build process.

Don't set MINIGZIP variable for ota scripts

Change-Id: I5aedcf3f303dafa63ba8a25ab7383c5186898840