InteractionManager now traverses in reverse when looking for a hit-test. This produces more accurate results with layered containers.
Merge pull request #630 from mattdesl/interactionmanager-fix

InteractionManager hit test now checks bottom-to-top
Fixed bug where hitArea was being checked after the children hitTest
collecting interactive sprites should not happen in reverse
Merge pull request #644 from mattdesl/bugfix-641

Bug fix: Siblings' event priority