Port SkBlurImage opts to SkOpts.

+268 -535 lines

I also rearranged the code a little bit to encapsulate itself better,
mostly replacing static helper functions with lambdas.  This also
let me merge the SSE2 and SSE4.1 code paths.

BUG=skia:4117

Review URL: https://codereview.chromium.org/1264103004
19 files changed