Select texture target based on pixel format

Adreno is not optimized for GL_TEXTURE_EXTERNAL_OES, making GPU
utilization (and power), high with GL_TEXTURE_EXTERNAL_OES for
RGB formats.

Change texture target from GL_EXTERNAL_TEXTURE_OES to dynamically
select between GL_EXTERNAL_TEXTURE_OES, and GL_TEXTURE_2D based
on the pixel format.

CM9 original author: Neti Ravi Kumar
CM9-Change-Id: I89ab1d60b23eef55442a9fd338b2a05b3304ce61

Change-Id: I9ea82f3fd1d9caea22d4b1da843f2dedb2daf51b

Signed-off-by: Daz Jones <yuki@thebronasium.com>

Conflicts:

	libs/gui/Android.mk
Prefer 16bpp surface formats

Adds a property to use RGB565 surface formats for the opaque
surface default, enabled by default.

Change-Id: Iac9bbc8292a863e2ab86093df3ecf218e4ec61e1

Conflicts:

	services/surfaceflinger/SurfaceFlinger.cpp
	services/surfaceflinger/SurfaceFlinger.h