Modify client side code to distinguish between api objects

In client work, especially writing tests, the term "scheduler" is overloaded in the code, and this makes diagnosing and debugging failures difficult.

An aurora API object contains a property named "scheduler", which is a reference to a SchedulerProxy. A SchedulerProxy, in turn, contains a property named "scheduler", which is actually a reference to a SchedulerClient.

As a result, code frequently reads "foo. scheduler.scheduler.something"; in tests, when you see a "scheduler" parameter, it's either a SchedulerProxy or a SchedulerClient, with no good way to distinguish. This is especially problematic when you see a test failure: foo. scheduler didn't get an expected call; what is foo.scheduler?

To clear this mess up, we should get rid of the "scheduler" fields, and rename them to make clear what they are: api contains a field "scheduler_proxy"; SchedulerProxy contains a field "scheduler_client".