Add libjpeg-turbo library (depends on yasm)
Mangle external function names to avoid conflict with libjpeg
Take advantage of direct color conversion (RGBA, BGRA, 565)
Prepare to use jpeg_skip_scanlines (when it is upstreamed)

BUG=skia:

Review URL: https://codereview.chromium.org/1180983002
31 files changed