Add some performance tests for things involving RLMObject type checking
Use name-based type checking for RLM types

Rather than pointer equality, to support having Realm statically linked
into multiple libraries which are then dynamically linked together,
which results in multiple copies of each Realm class. This is of course
not something you really want to do, but it can happen naturally for
unit test targets on iOS.

Closes #690.
Add support for running Objective-C tests on devices

Swift tests are exploding horribly on iOS 7.0, and I have been unable to
get Xcode to actually deploy working apps to iOS 8.0, so no swift
testing on devices for now.