remove globals from some map group parsers
don't use the old header parsing method
convert all_map_headers from a global
knock out some trainer group globals
one preprocessor macro needs trainer_group_maximum
pretty_print_trainer_id_constants to trainers.py
run_main -> main
pass around all_movements (not a global)
deglobalize map_internal_ids

Also, don't set global rom in the load_rom related methods. This will
nip everything for a while, but roms should be passed around as
references instead of globals.