show errors on track upload
When the user uploads a track that is not valid (e.g. without timestamps) a message should be shown. Currently (commit 1992a2ad) nothing happens but the track is not displayed in the map.
When the user uploads a track that is not valid (e.g. without timestamps) a message should be shown. Currently (commit 1992a2ad) nothing happens but the track is not displayed in the map.