Fixing OnDisconnect error handling and byte buffer resizing

[Per6]

when OnDisconnect has an error, then the server never removes the client, causing even more errors and problems.
also setting MaxPayloadSize to something bigger than initial just doesn't work.

i have fixed those in my latest commit in my fork, so just copy that over or something.
fixes

i also removed the copying of the whole array in tcp sending and restructured the recieve code for udp and tcp to be a bit better.

Edit: i just made a new commit since sending and recieving buffer can simply be the same thing.
Edit2: i just made a commit for a better rtt system, you can copy that too if you want.