Fix problem with megaregions where teleporting into a different region which already had a child agent would stop the eq working for the agent in the new region.

This was because the calculation as to whether a new agent was needed in the receiving region did not take megaregions into account,
unlike the original calculation when the user first teleported into the region.
This meant that on teleport, entity transfer would create a new CAP but this would be ignored by the viewer and receiving region, meaning that the EQ could no longer be used.
This would prevent subsequent teleport, amongst other things.
Currently, regions up to 512m from a megaregion are considered neighbours.