WIP merge server/client code

Singleplayer should be a special case of multiplayer
Reorganize files for unified src
Makefile generates dependencies, unified src
Remove common header, replaced by src/constants
Add include guards to all headers
Sources only include their own headers
Update some includes
Add missing includes
Combine Game,MultiplayerGame into Client.

And drop SingleplayerGame
Add simpler player constructor for client
Split Makefile for compiling/other
Update includes for controls. mv InputReader
Rebuild depends when sources change
Fix depend depends
Update cursor includes
Update player and game includes
Update grid includes
Update menu includes
Update message includes
WIP split up server code