Remove button release calls -- as the buttons are allocated via a factory method rather than alloc/new, and are not manually retained, they should not be manually released. See https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/MemoryMgmt/Articles/mmRules.html. Discussed with Jonty D.
Merge branch 'orientation' into orientation_split_out_parameter_strucutres