Add DTrace probes for compound disposable growth
Instruments template for compound disposable growth
Inline 2 disposables into RACCompoundDisposables

Empirically determined. There are few compound disposables with 3 or
more inner items.
Fix OOB array access in -initWithDisposables:
Add another disposable to +compoundDisposable… test
Merge pull request #829 from ReactiveCocoa/disposable-optimization

Object inlining and instrumentation for RACCompoundDisposable