bring back squisher (2/2)

This reverts commit 9e215451006657b1a6de26f83924e207ede99114.
always rebuild build.prop

Change-Id: I9a6f4706cdc3e0ca4e40acb1b00419d72a236f65
add global -Wno-unused-parameter to make gcc 4.8 happy

Change-Id: I58b163ce1221ec08d71b76e19fa69d369550dded
Revert "Include drawables for all densities - b/11270325"

This reverts commit 0068d25b4895162993118fe3b61d2775fa575e70.
Add Email package in build

Change-Id: I83413e8e88a3beb1bd9a926aee2d766148f82a5a
build: armv6-vfp.mk remove useless variables

There are some variables that are no longer needed, remove them

Change-Id: I41e307d7e0f249eabfb1f4d6e66b712bd039370a