Extract UserComment Exif data and show it at title

If Exif UserComment can be found, then use it as the image title. There
may be problems with the UserComment encoding as EXIF specifications
are pretty vague on that topic.
Move the map image to CSS
Map view for albums in galleria theme

This feature hacks galleria to show an openlayers map instead of the
picture. The feature is far from perfect but it already displays dots
for the geolocalized pictures
Don't show the Map link if there is no geotagged photo in the album
Map: fixed a bunch of tiny problems
map: update the map feature when changing image
map: update the picture in galleria when clicking a feature