extend SignalProducerType instead of SignalProducer
extend SignalProducerType instead of SignalProducer

removes the need for force casting :)

Moya/Moya,calt/Moya,petester42/Moya,jasl/Moya,AvdLee/Moya,callam/Moya,skywinder/Moya,swizzlr/Moya,gmertk/Moya,colinta/Moya,leonereveel/Moya,AvdLee/Moya,AvdLee/Moya,jasl/MoyaX,colinta/Moya,justinmakaila/Moya,calt/Moya,filograno/Moya,skywinder/Moya,wattson12/Moya,gmertk/Moya,SRandazzo/Moya,SRandazzo/Moya,wattson12/Moya,justinmakaila/Moya,Moya/Moya,filograno/Moya,leonereveel/Moya,justinmakaila/Moya,esttorhe/Moya,gmertk/Moya,calt/Moya,ashfurrow/Moya,swizzlr/Moya,callam/Moya,gmertk/Moya,Moya/Moya,ashfurrow/Moya,petester42/Moya,jasl/MoyaX,jasl/Moya,esttorhe/Moya