updated broadcast and channels, tests need fixing

broadcast/client.go

broadcast/interface.go

broadcast/method.go

broadcast/processor.go

broadcast/processor_test.go

broadcast/rsaToPublic.go

broadcast/rsaToPublic_test.go

broadcast/sizedBroadcast.go

broadcast/sizedBroadcast_test.go

broadcast/symmetric.go

broadcast/symmetric_test.go

broadcast/utils_test.go

channels/adminListener.go

channels/adminListener_test.go

channels/joinedChannel.go

channels/joinedChannel_test.go

channels/send.go

channels/send_test.go

go.mod

go.sum