Add additional checks for spawn/teleport

[y0014984]

• water
• buildings

[nomisum]

i already have a system in place in breaking contact that prevents spawning in water by "cheaply" checking a 2x2m place on map click:

vector worldPos = {coords[0], GetGame().GetWorld().GetSurfaceY(coords[0], coords[2]), coords[2]};
bool spawnEmpty = SCR_WorldTools.FindEmptyTerrainPosition(worldPos, worldPos, 2, 2);

when this 'cheap' test is successful a more extensive check for a larger empty position takes place.

[nomisum]

some teleport issues today still, sometimes affecting multiple people, sometimes only 1 or 2