Increase precision of lat/long at higher zoom levels

[kateler]

Summary
It's a common sharing technique to copy and paste the zoom/lat/long from a Maperture view. However, at high zoom levels the current precision of the lat/long is not enough to accurately reproduce the desired map extent.

Repro steps

• View this in Maperture
• Drag the map so it looks like this:
• use the "copy" tool to copy the zoom/lat/long
• use the "change" tool to paste the same zoom/lat/long back in and press Enter
• The map is redrawn and looks like the first map above

When trying to share a specific area, this can introduce confusion. At lower zoom levels, this precision is fine but at higher zoom levels, the precision should increase so that this offset doesn't occur.