Incremental improvements to bench graph generation

- make revision number a link to that change on code.google.com
- clean up display and add help text
- make revision lines show up a bit more (light yellow)
Review URL: http://codereview.appspot.com/4839053

git-svn-id: http://skia.googlecode.com/svn/trunk@2062 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed