Fixes to deal with rr 1.1.1

* Argument checking now cares about the order of hashes.
See gnip_data_sources_controller_spec.

* mock(MyClass).new(nil, 'foo', 'bar') { |obj| stub(obj).do_stuff } apparently used to
cause MyClass to produce valid stub objects (or at least not crash), but now
poisons future objects. "stub.proxy(MyClass) ..." is a viable replacement.
See table_copier_spec.

* Some sort of shenanigans (that also poison future objects) maybe related to
stubbing with nested let() statements. See dataset_statistics_spec.

Also fixed sporadic ordering problem in job_spec