Add a 'village' zoom level at 13 between town and neighbourhood
and a all locality-like objects for zoom 15. These zoom levels had
the same behaviour as the lower level so far. However, the distinction
for village and locality may be useful at times.
* remove traces of HTML output
* add details on artificial objects (see also #1671)
* add geometry output documentation for lookup
* deprecate query by ID via reverse endpoint
* remove /search/<query> query format, no longer supported
* explain better what reverse geocoding does
* lots of smaller fixes to wording
