VeNum optimizations

    jpeg-VeNum-optimization-of-IDCT-YCbCr-to-RGB-color-c

    Preserve registers D8-D15 when using VFP as specified by
    AAPCS v2.03

    Additionally had to split jdcolor-armv7.S into two files to
    resolve the issue of constants not being addressable in the
    code segment.

    Remove unused IDCT code

Change-Id: I93fed76a05a9c36458fd20390e5381b2d4ec9d37
libjpeg: Remove unused idct VeNum references
Porting jpeg_mem_src() from jpeg lib v8c

A new function jpeg_mem_src() is ported from jpeg lib v8c to support
decode/encode in memory.

Change-Id: Ifa3bb96ae2c1a4f3f84ca324e3ee5a65a1c87a6c