Document -rac_signalForDelegateMethod: memory mgmt
Avoid retain cycles between RACDelegateProxy and RACEventTrampoline.

Trampolines will always have a strong reference to their delegate proxy
for its lifetime, so we can safely have a non-retained back reference,
breaking the cycle.

Fixes #743.
Prefer dot-syntax over square-bracket syntax.
Merge pull request #751 from lukeredpath/bug/fix-retain-cycle-in-delegate-proxy

Avoid retain cycles between RACDelegateProxy and RACEventTrampoline
Merge pull request #750 from ReactiveCocoa/text-view-delegate-warning

Document that -rac_signalForDelegateMethod: requires the delegate to be set to nil before -dealloc
Merge branch 'master' into 2.0-development

Conflicts:
	ReactiveCocoaFramework/ReactiveCocoa/RACDelegateProxy.m
	ReactiveCocoaFramework/ReactiveCocoa/UITextView+RACSignalSupport.h