Add lco to PostgreSQL driver to have indexes created

[bartvde@…]

It would be nice if there would be a layer create option on the PostgreSQL
driver to have indexes created automatically.

I would suggest the following indexes:

CREATE INDEX [tablename]_geom_idx
  ON [schema].[tablename]
  USING gist
  (wkb_geometry);

CREATE INDEX [tablename]_oid_idx
  ON [schema].[tablename]
  USING btree
  (oid);

CREATE INDEX [tablename]_ogc_fid_idx
  ON [schema].[tablename]
  USING btree
  (ogc_fid);

And after this do a VACUUM ANALYZE;

[hobu]

This might be nice for 1.5 if there ends up being a bunch of other PG-related stuff going on this release.