GeoJSON rounding precision inconsistent between draw and editing

[cjhewett]

• Click rectangle tool
• Draw box
• Note GeoJSON using 15 decimal places
• Drag the feature with space+drag
• Still 15 dp
• Drag corners to resize
• Rounded to 7 dp

• All operations should round to the same precision (of which I agree that 7 dp is a good choice).
• Point / LineString / Polygon rounds to 7dp when drawing and editing
• Circle rounds to 15dp on drawing and editing