Change InterfacedActor<T> to InterfacedActor

[veblush]

CRTP (Curiously Recurring Template Pattern) is used for assigning an unique static member variable for each derived class T. This variable is for saving a table for message dispatching. It was quite easy to implement this with CRTP. But using CRTP has drawbacks like:

• Not easy to read.
• Verbose. (e.g. LongLongActor : InterfacedActor)
• Error-prone. (e.g. Cat : InterfacedActor)

So let's strip CRTP away from InterfacedActor.