Removed dead declaration.
Returned ScheduleHandles from FuncRefVar/FuncRefExpr assignments.
Rename ScheduleHandle to Def. Add test.
Naming cleanup. Def -> Stage. Reduction -> Update.
Corrected up some comments in RDom.
Merge branch 'master' into named-updates
Added typedef for backwards compatibility with code using ScheduleHandle.
Merge pull request #412 from halide/named-updates

Named updates