schemas/vegbien.sql, inputs/SALVIAS/validations.sql: added _plots_10a_aggregate_observation_individual_counts, for use in debugging diffs in _plots_10_count_of_individuals_per_plot_in_each_proj

schemas/util.sql: create_if_not_exists(): also support `CREATE FUNCTION` (by handling duplicate_function exceptions)

schemas/util.sql: mk_keys_func(): create the keys() function directly from the keys record type, to support creating just a custom keys record type rather than also a custom keys() function (which is fairly complicated to do, thanks to the need to define a separate custom return type)

bugfix: schemas/util.sql: relation_type(relation_type_char "char"): need to handle TYPEs as well, because these are also listed in pg_class (and should be deleted by drop_relations_like())

schemas/util.sql: added show_types_like()

bugfix: schemas/util.sql: functions marked IMMUTABLE: changed to STABLE or VOLATILE where IMMUTABLE would cause preemptive inlining (http://vegpath.org/links/#PostgreSQL:%20Documentation:%209.3:%20Function%20Volatility%20Categories%20**)

bugfix: schemas/util.sql: functions marked IMMUTABLE: changed to STABLE or VOLATILE where IMMUTABLE would cause preemptive inlining (http://vegpath.org/links/#PostgreSQL:%20Documentation:%209.3:%20Function%20Volatility%20Categories%20**)

schemas/vegbien.sql: locationevent: documented `UPDATE locationevent SET place_visit_id = place_visit_id` runtime (>~1 h)

schemas/util.sql: added relation_type(regtype) so drop_relation() would work on TYPEs, too. TYPEs are sometimes used as a function return type linked to a particular table (eg. in the keys() functions), and should be dropped along with the table by util.drop_relations_like().

schemas/util.sql: drop_relation(regclass): support any type that has a util.relation_type()