added lib/runscripts/data.pg.sql.run (analogous to schema.pg.sql.run for data-only SQL scripts)

added lib/runscripts/file.pg.sql.run and use it in schema.pg.sql.run

added lib/runscripts/schema.pg.sql.run and use it in inputs/.TNRS/schema.sql.run

inputs/.TNRS/schema.sql: generate from the DB using `rm=1 inputs/.TNRS/schema.sql.run export_` instead of being a hand-edited file. this makes it much easier to edit the (now frequently-changing) TNRS schema directly in pgAdmin (which is graphical), rather than having to manually copy SQL changes from pgAdmin to the file.

inputs/.TNRS/schema.sql.run: export_(): added usage

added inputs/.TNRS/schema.sql.run, which syncs schema.sql with the DB

bugfix: lib/sh/db.sh: pg_dump(): don't default $struct flag to on, because both structure and data should be printed by default

lib/sh/db.sh: pg_dump(): added create_schema= flag to remove CREATE SCHEMA statements (useful if the schema already exists)

bugfix: lib/sh/util.sh: set_fds(): remove empty redirects resulting from using `redirs= cmd...` to clear the redirs and then using $redirs as an array

fix: lib/sh/util.sh: set_fds(): documented that it does not currently support redirecting an fd to itself (due to bash bugs that require the dest fd to be closed before it can be reopened)