Improve display for coordinates

[mkroetzsch]

As an obvious first step, coordinates should be formatted in the common style with degrees, minutes, and seconds rather than decimal degree values.

A further improvement would be to display a map in the collapsible area where the references are.

A further improvement would be to do this even in statements that have the coordinate in a qualifier only (e.g., place of burial).

[mkroetzsch]

Mostly fixed by merging #112 (coordinate display and map). The third point may not be so essential, as it affects few statements only.