Fix Stamen tile URLs for SSL compatibility. (#1950)

- Thanks to Leila Gonzales for the fix.
- See https://github.com/stamen/maps.stamen.com/issues/167 for details.

config/vufind/geofeatures.ini

@@ -28,11 +28,11 @@ basemap_url = https://maps.wikimedia.org/osm-intl/{z}/{x}/{y}.png
 basemap_attribution = "<a href=""https://wikimediafoundation.org/wiki/Maps_Terms_of_Use"">Wikimedia</a> | &copy; <a href=""https://www.openstreetmap.org/copyright"">OpenStreetMap</a>"
 
 ; stamen-toner
-;basemap_url = http://tile.stamen.com/toner/{z}/{x}/{y}.png
+;basemap_url = https://stamen-tiles.a.ssl.fastly.net/toner/{z}/{x}/{y}.jpg
 ;basemap_attribution = 'Map tiles: <a href="http://stamen.com" title="Map tiles by Stamen Design, under CC BY 3.0">Stamen Design</a> | Data: <a href="http://openstreetmap.org" title="Data by OpenStreetMap, under ODbL.">OpenStreetMap</a>'
 
 ; stamen-terrain
-;basemap_url = http://tile.stamen.com/terrain/{z}/{x}/{y}.png
+;basemap_url = https://stamen-tiles.a.ssl.fastly.net/terrain/{z}/{x}/{y}.jpg
 ;basemap_attribution = 'Map tiles: <a href="http://stamen.com" title="Map tiles by Stamen Design, under CC BY 3.0">Stamen Design</a> | Data: <a href="http://openstreetmap.org" title="Data by OpenStreetMap, under ODbL.">OpenStreetMap</a>'
 
 ; cartocdn-light
@@ -85,7 +85,7 @@ basemap_attribution = "<a href=""https://wikimediafoundation.org/wiki/Maps_Terms
 ; graticule: true or false. Default is false. If graticule is true a lat/long grid will be
 ;                displayed on the map.
 ;recordMap = false
-;mapLabels = 
+;mapLabels =
 ;displayCoords = false
 ;graticule = false