Features/separateupdatelocs

This is a proposal to create a separate script for updating locations, taking the `--update-locations` option out of gpx2spatialite and adding `gpx2spatialite_updatelocs` in the /bin folder.

The script also has an `--all-locations` option which resets all locations to unknown and then uses a different method to lookup and redefine all trackpoints in the database. This method is much faster than the one used for updating unknown locations only.