GrCustomStage Renaming Part 5

Stuff found by searching for "stage".

R=robertphillips@google.com
Review URL: https://codereview.appspot.com/6772043

git-svn-id: http://skia.googlecode.com/svn/trunk@6089 2bbb7eff-a529-9590-31e7-b0007b416f81
32 files changed