Add -[RACSequence objectEnumerator].
Avoid capturing self in blocks when not necessary.
Tag the weak stream as unused because NSAssert only expands in debug builds.
Merge branch 'master' into racsequence-enumerator
Fixed comments and added synchronization around property access of RACSequenceEnumerator.
Added deallocation test for -[RACSequence objectEnumerator].
Merge pull request #280 from EnthusiasticCode/racsequence-enumerator

Add -[RACSequence objectEnumerator].