build: Add support for PRODUCT_COPY_FILES_OVERRIDES

 * We may have a case where prebuilts need to be built from
   source instead based on an externalized config.
 * New directive takes a list of destination files to remove from
   PRODUCT_COPY_FILES so that other instructions can be supplied.

Change-Id: I7feff16440e54d1676ffddbbd96d5947efa43ede
Kernel : Use Linaro 4.8.2 Toolchain

Change-Id: I25f67548af4244c20179437ad4ee0c68aaf8213a

Conflicts:
	envsetup.sh
Enable gesture typing - (3/3)-delete the libjni_latinime package in favour of prebuilt libjni_latinime

Change-Id: Id06777518f0d0e87aaeab8fb105224ae29ed9e77