SC31 POI 'quest' version

This version adds the ability to show several types of POIs. Touching a POI shows some information (i.e. what it is)

Some problems:

• the quests simply re-use existing images, and don't have good titles. Each quest adds one color of POI
• not all POIs are displayed. You should check or adjust which elements are displayed (and which are not!) to avoid creating notes for existent but not displayed POIs
• be careful near the edges of downloaded areas, often some POIs are shown and some are not. These edges are easy to miss when zoomed in, and they are not sharp (POIs mapped as areas can be shown outside the downloaded area)
• when clicking on some POIs, the app simply crashes (e.g. sport=table_tennis without leisure=pitch)