Fixed mulitplayer issues

Fixes #23

The issue:
-Sometimes when starting a mulitplayer game an error occurs
	-On server : stuck in InGame_Wait, does not respond to
	mouse input
	-On client : stuck in mulitplayer menu

Cause:
-The client connects to the server properly, but the server doesn't
accept the connection before recieving GameJoined message
-This causes sending of GameSettings message to fail which means the
can't move on from the above state

Note:
-Sometimes the server accepts the connection BEFORE recieving the
GameJoined message. In this case, everything works properly.

The solution:
-NetManager::Update is now called when recieving a GameJoined message instead
of in GameManager::Update.
-NetManager::Update is now called before trying to send GameSettings.
This means the connection will be accept in time, and the sending won't
fail.