Replace 'confirm' with new 'safe_peaceful' option

This lets the player choose what happens when they move into peaceful
monsters:

 * yes - (default) do nothing; "You stop for the foo."
 * no - hit them anyway, like confirm off
 * ask - prompt to hit, like confirm on

Having this set to 'yes' should cut down on spurious confirm prompts
when accidentally walking into peacefuls, and does not waste a turn,
consistent with answering 'n' at the prompt.
NH4: Show slots needed to advance in #enhance menu

Skills that can be advanced will show something like "(2 to advance)" on
the right side of the skills menu.

Compared to NetHack4, this isn't shown if raising skill levels without
limit in wizard mode.

Show slots needed to advance on the #enhance menu
Alex Smith <ais523@bham.ac.uk>
529b2762e71d489863ccbbc575ff7788148f7dc5
Show available skill slots in #enhance menu

The number of skill slots that a character has for advancing skills is
now shown in the title of the #enhance menu.
Add skills option to Ctrl-X screen

Pressing 's' at the menu shown with Ctrl-X now shows the #enhance menu.
NH4: Deliver objects through hole to correct level

Also fixes messages for boulders and statues destroyed out of sight.

rloco() and scatter() called by deliver_object() with the MIGR_RANDOM
method assumed objects were being delivered to the current level.

Compared to NetHack4, this fixes a stray 'level' in the new rloco_pos()
function (this bug also exists in NetHack4), and archeologists that
break historic statues out of sight now "feel guilty for some reason."

This is meant to go with commit cc2a91866d (NH4: Eliminate object
migration).

Deliver objects falling through a trapdoor to the correct level.
Jared Minch <jmminch@gmail.com>
92148a731cfada84102b733f80b0f4ae4ef419b8