Remove old enums

Removes the old_t_* and old_f_* enums and the function to access / load them.

Fixes http://smf.cataclysmdda.com/index.php?topic=7055.0

There was a lonely `old_f_skin_wall` in `map::bash` which is certainly wrong.

I changed the condition `if (g->m.ter(p->posx, p->posy))` in `iuse::hacksaw`. This is equivalent to `if (g->m.ter(p->posx, p->posy) != 0)` and 0 is `t_null` so it checks for "not `t_null`", which is (hopefully) always true. If that condition turns out to be false, it would leave the function without any message or sound or resulting item, which is not good either. This was introduced by 0a01240cb86ca427ec6890348b6f313a3cc19207