Feature update (v4.5): Filter category results

This update brings a very exciting feature: You can filter category results by certain criteria. Every category has a filter for the title of the map features (in fact it queries the tags name, operator and ref, including the localized tags like "name:en"). Many categories have additional filters, e.g. for the type of object (Example: filter the emergency category by type, e.g. Police, Fire Station, Hospital, ...). (Requested here: #33, #70)

Gastronomy category filtered for pubs in Birmingham, showing possible additional filters.

Further minor changes since the last upgrade:

• The search has been moved into the global toolbar
• The gastronomy category now includes Food courts.
• The landuse category shows type of residential areas.
• User wopfel added a few shop icons