Reorganised load/save code, looking for a bug

Changed the names of some "world" feature save functions.

Called all the "world" load/save functions from the main script's
OnGameModeInit instead of hooks (hooks with y_hooks don't seem to follow
the include order) this way the order of loading/saving is controlled.

(After reports of a bug with safeboxes not saving, added back some debug
prints.)