Add neon optimized color conversion.

Implements all merged upsampling color conversion functions in
NEON assembler. Optimizes web and gallery application use case.
Adds NEON optimized merged upsampling/color conversion for RGBA8888.

Change-Id: I638098d520d513bc41c003ebed59cfa33558c2bd
Signed-off-by: Patrik Ryd <patrik.ryd@stericsson.com>
Signed-off-by: Henrik Smiding <henrik.smiding@stericsson.com>
Add neon optimized dequantization and inverse DCT.

Implements unscaled and scaled dequantization
and inverse DCT functions in Neon assembler.
Optimizes web and gallery application use case.

Change-Id: Iee4ebfbad7c0dd049e7d9c3fc4b48aca0df208d3
Signed-off-by: Patrik Ryd <patrik.ryd@stericsson.com>
Signed-off-by: Henrik Smiding <henrik.smiding@stericsson.com>