Some cleanup

Adde crosshair layer
Fine tuning of buildings layer
Some visual cleanup

Switched to overpass compatibility (xapi) URL for buildings

Switched to overpass xapi URL to fetch the building (main API was not reliable enough).
Some limitation are present with this API (no more ways, relations fetching possible per identifier) so some building will be "incomplete".

New dark mode

New dark mode

Implemented gpx layer

Added .gpx file handling layer for display tracks on terrain

Initial preview release

First preview release to play with