Updated the README with details of the new PTPusherChannel API.
Updated the README with details of the new PTPusherChannel API.

alloy/libPusher,andreaperizzato/libPusher,andreaperizzato/libPusher,alloy/libPusher,andreaperizzato/libPusher,alloy/libPusher,alignd/libPusher,hamchapman/libPusher,lukeredpath/libPusher,LoyoChengdu/libPusher,hamchapman/libPusher,lukeredpath/libPusher,LoyoChengdu/libPusher,LoyoChengdu/libPusher,LoyoChengdu/libPusher,alignd/libPusher,alignd/libPusher,lukeredpath/libPusher,hamchapman/libPusher,lukeredpath/libPusher,alloy/libPusher,andreaperizzato/libPusher,alignd/libPusher,hamchapman/libPusher