move interpolaton computation into indexing step

The interpolaton computation needs information from the osm2pgsql
slim tables which may not be available when the data is inserted.

Insertion now only adds a line with basic address information to
location_property_osmline. The line is then split during the
indexing, leading to more lines (which are complete in that case)
being inserted.

Fixes #598.

sql/tables.sql

@@ -167,6 +167,8 @@ GRANT SELECT on location_area to "{www-user}" ;
 -- insert creates the location tables, creates location indexes if indexed == true
 CREATE TRIGGER placex_before_insert BEFORE INSERT ON placex
     FOR EACH ROW EXECUTE PROCEDURE placex_insert();
+CREATE TRIGGER osmline_before_insert BEFORE INSERT ON location_property_osmline
+    FOR EACH ROW EXECUTE PROCEDURE osmline_insert();
 
 -- update insert creates the location tables
 CREATE TRIGGER placex_before_update BEFORE UPDATE ON placex