Fix reconnection bug

How to reproduce:
-Star a new multiplayer game
-Leave the game before anybody connects
-Create a new multiplayer game.
-The new TCP connection will now not work properly, givinb the error
message that socket is null
-In addition, the previous game started will not be removed from the
list in server

Fix:
-After every server connect, the 100 will be added to the port number.
-The above is a temporary fix, it should not be neccessary to change
port number. Instead the connection should be destroyed properly, even
when none is connected on the other end.
-The GameServer now uses GameID to compare games
Added Bullet

-Added Bullet struc that holds speed and calulates new pos in
Update(delta).
-Added bulletList, a vector that holds all bullets in Renderer and
GameManager.
-Added UpdateBullets() in GameMnager. This simply runs Update( delta ) on
all bullets.
-Added generation of a new Bullet when pressinf the f key

TODO:
-Implement hitting and destroying of Tiles.