Geographic name search in map window of "New Excerpt"

[sfkeller]

Implement a geographic name search in map window of "New Excerpt".

There are several options (esp. also for Leaflet), e.g.

• Stefano Cudini's: http://labs.easyblog.it/maps/leaflet-search/
• Nominatim: http://www.openstreetmap.org/search?query=Uster
• OSMNames: http://osmnames.org/#q=Uster

A use case is that a user wants the data of a town or city, where initially he knows only the name (example "Uster town"). He then can enter "Uster" in the search widget and choose "Uster town".

In addition, the search dialog can accept bbox coordinates, e.g. in CSV format from http://boundingbox.klokantech.com/ => bbox of Uster town in CSV format "8.677501,47.320152,8.760421,47.383873" (without parantheses).