colorconvert: YUV420 Planar support

Change-Id: I9b7c434033baddab10e7c98efc1e401d7c94a531
libc2dcolorconvert: Add flag for RGBA8888 endianness correctness

- C2D API by default expects the alpha byte in RGBA8888 at the LSB
- We add a flag requesting it to look for alpha at the MSB instead.

Change-Id: I9761564bc5e1381624becd56ee06fd5822c47597

Conflicts:

	libc2dcolorconvert/C2DColorConverter.cpp