Patch provided by Ricardo Ramos Massaro.

BISG only attempts to set the dsn and load_bisac() if a DSN is specified or autodetectable from configdir

work properly, but we can't test for it because the module itself
isn't versioned.

add missing dependencies

autodetected input encoding (force UTF-8 there as well)

Fix buggy syntax on genepub (first argument now overrides output file, not input opf, documentation fixed)

Change subcommands so that they return instead of instantly exiting so one command can be called from inside another.