Ignore hero flag spawnpoints in collision

[Socialdarwinist]

Though a hero flag spawn point should not be placed inside of collision, the server should not present flags there either, to prevent nonetheless potential blunders in entity placement that can be caused by various circumstances – a misclick by some jerk, attention outrun by other attention, or a misbehavior of the map editor, wherewith there is always haunting the possibility of a source of rage in a map lavish in consuming time for spotting it.

[Socialdarwinist]

Ref teeuniverse/teeuniverse#158