called_from_main_loop_9: Structure.
Split declared constants into enumerations and flags.

* Fill out all keyboard port constants.
Be more firm in documentation of unused locations.
Fix old function call names.
Remaining divide_array_by_8_with_rounding -> divide_array3_by_8_with_rounding.
Adjust keyscan_cancel so the lines match the assembly.
queue_message_for_display takes one arg.
Treat symbols like $800D as vars - no need to deref.
Ignore *.o *.d and 'build' dir contents.
sound_3030 is the 'pick up item' sound.
indoor_room_index -> room_index.
Split consts and enums out.