added -rac_signalForSelector:
don't need that anymore
clarify wording
more clarification
assert if the method has an existing implemenation
send the argument instead of the receiver
corrected the method signature
I guess conditionalize the test based on asserts
mark unused
derp
Add convenience method for delayed schedule on RACScheduler

Method `-after:schedule:` takes dispatch_time_t argument that is in nanoseconds.
New method `-delay:schedule:` takes NSTimeInterval as argument (in seconds) and
calls `-after:schedule:` with calculated dispatch time. Method is implemented
in suberclass and is not abstract.
Update README.md
implemented forwarding of completed and error events to RACGroupedSignal when using -groupBy:
improved source code
Merge pull request #390 from zlajo/feature/group_by_event_forwarding

implemented forwarding of completed and error events to RACGroupedSignal when using -groupBy:
less lulzy RAC-less parallel work example

h/t @ddeville
Mention that iOS targets need -ObjC
style.
Merge pull request #395 from ReactiveCocoa/readme-objc

Update README to mention that iOS targets need -ObjC Linker Flag
Rename `-delay:schedule:` -> `-afterDelay:schedule:`