inputs/REMIB/Specimen/postprocess.sql: map_nulls() derived cols: documented total runtime (7.5 min on vegbiendev)

inputs/REMIB/Specimen/postprocess.sql: map_nulls() derived cols: updated runtimes for map_nulls() inlining, which created a speed improvement of 7x for the numeric columns and 2.5x for the text columns (292563.362->41929.772 ms and 83640.424->35690.797 ms, respectively). note that the map_nulls__coord__*() calls could be optimized further by combining the successive map_nulls() calls into one, with the hstores merged.

schemas/util.sql: map_nulls(): documented that inputs/REMIB/Specimen/postprocess.sql > country also shows that inlining is now happening properly. note that the speed improvement due to inlining is not as much, %wise, when the values util._map() is run on are long strings instead of the short strings used in the initial profiling. this is because a greater % of the time is spent in system functions such as hstore>text, which are not affected by the inlining because they are run either way.

schemas/util.sql: map_nulls(): use new nulls_map(). proper inlining (i.e. same runtime before and after change) has been verified with the following profiling query:
SELECT util.map_nulls(array[1, 2, 3]::text[], v) FROM unnest(array_fill(1, array¹⁰⁰⁰⁰⁰)) f (v)

schemas/util.sql: added nulls_map(), for use with _map()

lib/runscripts/table.run: postprocess(): added remake action that calls trim_table()

lib/runscripts/table.run: added trim_table(), which calls util.trim(regclass, regclass)

lib/runscripts/table.run: map_table(): added remake action that calls reset_col_names()

lib/runscripts/table.run: added reset_col_names(), which calls util.reset_col_names()

bugfix: lib/runscripts/table.run: map_table(): moved $map_table to global var so it can be used by other functions