lib/sh/db.sh: added set_large_table alias, used to set to_file's $del flag based on $limit

lib/sh/util.sh: added exit2bool()

lib/sh/util.sh: int2bool(): renamed to int2exit() because it actually sets a boolean exit status rather than returning a boolean string

bugfix: lib/sh/util.sh: to_file(): also kw_params the other kw params if_not_exists, del

lib/sh/db.sh: mysql_cmd(): use --quick to avoid buffering entire result (which is slow and memory-intensive for large result sets). this option applies to both mysql() and mysqldump().

lib/sh/make.sh: self_make(): documented that it should be preceded by set_make_vars

bugfix: inputs/GBIF/_MySQL/GBIFPortalDB-2013-02-20.data.sql.run: ^.preamble.sql/make(): need to run set_make_vars even though the make vars are not used, because set_make_vars sets $_remake, which is needed by self_make

lib/sh/make.sh: set_make_vars: echo_vars $_remake to help debugging

bugfix: lib/sh/util.sh: to_file(): need to run invoked cmd using redir so that >$stdout redir is applied properly when cmd is a shell function instead of an external command (external commands were already redirected properly because command() calls redir). this fixes a bug in inputs/GBIF/_MySQL/GBIFPortalDB-2013-02-20.data.sql.run ^.preamble.sql/make(), where the generated file would be output to stdout instead of to the file because to_file()'s command was a shell function, and therefore the redirection was not applied. this fix requires redir() to be a separate function from command(), because command() does many things that are only applicable to external commands.

lib/sh/util.sh: redir(): override save_e and add `unset redirs` so error handlers are not redirected