Improvements to opac

[rogercgui]

This release fixes bugs, improves performance and introduces new features.

• Fixes the behaviour of the language selection;
• Fixes the loading of the tag for displaying protected images;
• Fixes the display of OPAC Analytics (see the central module);
• Fixes the display of facets, as they were not being shown in some cases even though they existed;

Implementation

• The new function checks whether the database has any IP access restrictions.