skpdiff: add ability to write the diff scores in a csv file (one line per pair of diff images, with the result of each diff engine)

Review URL: https://codereview.chromium.org/19786004

git-svn-id: http://skia.googlecode.com/svn/trunk@10194 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed