Required:
-* Cache map tiles in the indexedDB
-** Use an intelligent algorithm to automatically try (async) updating tiles if they have a certain age
-*** If they have changed, possibly also try (async) updates of other cached zoom levels covering this area
-** Clear cached tiles option
-* Find the bug that messes up the display when panning on not fully loaded tiles (web connection down)
+* Improve tile cache:
+** If cached tiles have changed, possibly also try (async) updates of other cached zoom levels covering this area
+** Pre-cache tiles in adjacent areas and possibly zoom levels
* Show a notification when we are loading tiles or saved data
* Display length and duration of track
* Display movement speed
* Display location accuracy
* Show a better visible marker for the current location, possibly also indicating movement direction/speed
* Support pinch zoom gestures
-* Smoother animations for panning
* Smooth animations for zooming, probably using some canvas magic
* Use available larger/smaller tiles with resizing as loading placeholders while zooming in/out
* Save GPX tiles to the web (OSM? Public cloud service? Private service?)