Allow override of device asserts, including multi-device support.

Set in board file with TARGET_OTA_ASSERT_DEVICE.
(cherry-picked from commit 0f452f2)

Change-Id: I3d06bdc0e3e26bde0c0e646accd050364f9713b9
add no_assets.option
Change-Id: I489e7b965aa2e4286ebacd64006522a5d206f2db
new variable TARGET_RECOVERY_FSTAB

Currently the source file recovery.fstab has to be located
in $(TARGET_DEVICE_DIR)/recovery.fstab).

To allow multiple similar CM products to share one recovery.fstab
file this patch introduces the variable TARGET_RECOVERY_FSTAB.

Change-Id: I51961f5a1665023001c9857e13008a2ca44529ee

Conflicts:
	core/Makefile
build: fix target header overlay

LOCAL_C_INCLUDES as defined by the makefile should be put AFTER
the overlay includes so the overlay always takes precedence.

Change-Id: I489b2aab6dbacd9122d834f85e07b63ed1271f07
test -O2 flag