TODO

- overlays
  - general shape render overlay
  - overpass-api overlay
  - building model overlay

- cache:
  - collect tiles from 4 zoomlevels into one cache-tile (GEM-File?)

- labeling
  - use relevance tag, sort labels by relevance for faster dynamic placement
  - throw out overlapping labels with less relevance!
	- use separate datasource?
  	this would allow for reuse in multiple zoomlevels and
  	reducing the problem of tile clipped ways
  - text renderer for paths
  - interface for different placement algorithms
  - support icon+text items


- extract map position animator
  - add smooth fly-to

- integrate libosmscout or similar for offline maps/poi search and routing

- gl-compositing of overlay item bubble