SSE2-ified S32_alpha_D32_filter_DX (refactoring to come).  Also shaved a few
cycles off the SSE2 blends.

Review URL:  http://codereview.appspot.com/171055



git-svn-id: http://skia.googlecode.com/svn/trunk@456 2bbb7eff-a529-9590-31e7-b0007b416f81
5 files changed