A couple of last-minute patched / bugfixes to mitigate the probability of collisions...

A couple of last-minute patched / bugfixes to mitigate the probability of collisions between user controlled aircraft and AI traffic.
  * AI aircraft distance to user proximity detection works again (lat/lon were inverted).
  * The parking uses by the user aircraft is marked as such to prevent it being reused by an AI aicraft
  * AI aircraft won't receive permission for pushback until the user aircraft is at a fair distance.