Fixes error when importing csv files with the_geom columns
Removes export specs
Removes some legacy code and fixes user spec
Fixes importer issues

* Run VACUUM FULL on the importer and check user quota after that. We cannot
  run this operation on the table model because VACUUM FULL doesn't play well
  when there are opened transactions.
* Process the_geom column on csv files (previously you had to rename it to geojson)