Cache x,y plot locations

[wcampbell0x2a]

When only adding an aircraft, save the new x,y location with the icao as the hashmap key with the new x,y position.

When changing the local_lat, local_long, we need to refresh the entire set of x,y since they rely on the relative position of the antenna.

[hcm444]

Is this like a hashed BST? The reason I asked this is because in a chess game for example, we hash the images with a binary search tree in this way and optimize performance we keep reloading the images over and over again.