Removed render manager queue + code conventions on gamemap + creature vision debug

To test the creature vision debug, open the console and write "visdebug creatureName"
That will display every tile the given creature sees. Note that it clearly shows that there is a problem on how visible tiles are computed (especially on a 1 tile wide corridor).
Note also that this command is available on the server only. And if you use it, every client will see the visible tiles.

If the creature whose vision is displayed is pickedup, the tiles won't be displayed until it is dropped.