minor adjustment to reverse zoom translation

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.

docs/api/Reverse.md

@@ -92,7 +92,10 @@ In terms of address details the zoom levels are as follows:
   5   | state
   8   | county
   10  | city
-  14  | suburb
+  12  | town / borough
+  13  | village / suburb
+  14  | neighbourhood
+  15  | locality
   16  | major streets
   17  | major and minor streets
   18  | building

lib-php/ReverseGeocode.php

@@ -40,10 +40,10 @@ class ReverseGeocode
                       9 => 12,
                       10 => 17, // City
                       11 => 17,
-                      12 => 18, // Town / Village
-                      13 => 18,
-                      14 => 22, // Suburb
-                      15 => 22,
+                      12 => 18, // Town
+                      13 => 19, // Village
+                      14 => 22, // Neighbourhood
+                      15 => 25, // Locality
                       16 => 26, // major street
                       17 => 27, // minor street
                       18 => 30, // or >, Building