Only the owner, plot owner, plot friends and plot admins should be able
to see the plot boundary. Randoms just use it for griefing.
Also renamed the targetX variables to the more appropriate doorX in
fn_check_access since they are only used if the target is a door.
Access control for upgrade and downgrade is now included in
fn_selfActions as per #1706
I moved _upgrade down in fn_selfActions so it is only checked it if the
right conditions are met.
Fn_check_access provides the same functionality and more.
Removed folders that only contained a single file to clean things up.
Also added epoch tag friendly code to vanilla player_updateGui for now.
