Changes for FOW
- Related as much as possible events to tiles
- The rooms/traps are not notified to clients anymore. Only the tile meshes are refreshed (on the visible tiles)
- Creatures do not use sounds anymore. They send generic messages to play sounds in a given place
- Many server messages have been removed
- Messages are only sent to the concerned players (nearly no message is sent to every player anymore)
- Most messages are sent only to players with vision. For example, creature animation change is sent only to players who actually see the creature.
- On client side, only the visible entities are notified. When vision is lost, tiles are not refreshed and most entities (like creatures or most rendered entities) are removed from the gamemap. They are added again when vision is gained.
- Because of this, creature network embeds more information (such as animation info, ...)
- For now, creature sounds are only sent to players who have vision on the it. If we want to change that (like it was done in DK), it can easily be done

fixes #295
- Changed GameEntity::getPosition to return a const Vector& instead of Vector
- pass MapLight name to clients
Fixed room/trap cost preview on client side
Added a console command to give vision to every connected client
To test it, in the console, write:
icanseedeadpeople
change color of tiles without vision (on client side) and allow to drop creatures only on tiles with vision
Make ennemy claimed walls not selectable on client side
Taint only ground dirt/gold tiles and claimed ones (ground or wall) when the player do not have vision
Merge pull request #394 from hwoarangmy/development

Implementation of server side FOW