Slight bug in the TTN map display code

Not very important, but it explains what I have seen before. I placed a gateway online and added it’s co-ordinates. Later on the gateway page I noticed that the gps co-ordinates were displayed to 3 decimal places. I had configured to 6 decimal places as pulled from google maps or something like that. I then changed the configuration to use 3 decimal places and now it shows up as an additional gateway very close to each other, despite that the gateway ID is shown as identical. I had always thought that someone had two gateways when I saw that in the past.