- First step towards unified use of scopes. Will enable
further simplifications.
- Removed various ForEach iterators in favor of the existing
accessor methods, for a thinner API.
- Renamed outer/Outer to parent/Parent for scopes.
- Removed check.lookup in favor of Scope.LookupParent.
R=adonovan
CC=golang-dev
https://golang.org/cl/9862044