Deprecate -sample:
Remove "Block" in skip/takeWhile, deprecate skip/takeUntil
Deprecate -scheduleRecursiveBlock:
Deprecate -any and -all operators
Remove unused RACTuple methods, rename others
Deprecate -groupBy: and RACGroupedSignal
Reimplement -aggregate:, deprecate factory version
Reduce the number of values tested with replaying

Signal naming causes huge delays here (after the changes to
-array/-collect/-aggregate:), and the number isn’t important to the
correctness of the test.
Deprecate -then:
Update README example
Revert "Deprecate -sample:"

This reverts commit 3c26b7a17c3f61c0f0c421f3b906f74e04edadcd.

Conflicts:
	ReactiveCocoaFramework/ReactiveCocoa/RACSignal+Operations.h
	ReactiveCocoaFramework/ReactiveCocoa/RACSignal+Operations.m
Merge pull request #979 from ReactiveCocoa/api-cleanup

API cleanup