NoteService should be the only class with access to NoteDao;
nowhere else should NoteDao be accessed directly.
Channel dependencies are static in PacketProcessor, for now.
Ideally they would be injected in the constructor,
but since the constructor is private and I don't want to open
up that can of worms, I'll leave it like this.
At the very least, now we have a way of injecting services into
the handlers. This will make further restructuring way easier.
Split into 1 LoginServer and 1 ChannelServer per channel.
There is still a lot of cleanup and refactoring to be done.
Currently, the reliance on IoSession holding client state
is the most pressing issue to be addressed.
