Fixed DotNetty

[s074]

Fixed a couple of bugs, including:

• Packets are now decoded into frames properly. Used LengthFieldBasedFrameDecoder for decoding individual packets.
• When sending the same packet to multiple clients, such as in the BroadcastPacket method, the refCount in the message buffer would get decreased to 0. To fix this issue I had to completely refactor the way outgoing messages are handled. Now ServerPacket implements the IByteBuffHolder interface and holds the outgoing message buffer. The message composers will not hold the message buffer anymore, they now extend from MessageComposer instead, which just provides a method for writing the packet to the ServerPacket buffer.

One thing to note though was that features such as restriction of connections per IP were not implemented. Maybe will do that in another PR.

[Diddyy]

I've tested this on localhost, works flawlessly as expected. No breaking changes as a result.
+1 for this!
@Sledmore

[dotmbf]

Hey, first chance I get I'll check this out.

[Sledmore]

Awesome, I'll give this a look sometime tonight before merging it - but thanks for your contribution!

[IDjinn]

I didn't knew this repo was some users contributing to it... Maybe I make some here some my edits to better performance code