Required:
-* Cache map tiles in the indexedDB
+* Improve tile cache:
** 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
+** Pre-cache tiles in adjecent 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
-* Full screen mode
* Save GPX tiles to the web (OSM? Public cloud service? Private service?)
* Better GPX saving implementation [blocked by missing web APIs]
+** Set file name to save into to a good default (date + maybe some location name)
Nice To Have: