The bot should take into account reachabilit of the units

[kant2002]

During game, marines start chasing overlords, and he move itself outside of platform which, in the location which is unreachable by the marines fire. They still try to attack him, even he don't move at all.

This is similar to issue which arise during tournament with Iron bot when he create wall from building which lead to bot instead of targeting building target units after the wall.