Port WXS's drunken boxing patch.

This patch introduces drunken boxing. The drunken throw effect is broken
and had to be removed. Also, drunken boxing is now enabled via a birth
option rather than at compile time.

What follows is the original drunken boxing description taken from it's
authors website: http://nethack.atarininja.org/~wxs/patches/nethack/nethack-343-drunkenboxing.txt

Drunken Boxing spec

Purpose
    Make the weaponless Monk a more interesting and capable endgame
    character without upsetting game balance. This is accomplished
    by introducing a new ability at a certain level similar to the
    Drunken Boxing style of fighting depicted in numerous places
    (to spectacular effect in the Jackie Chan film Drunken Master).

Requirements
    - the player must be a Monk - the player must have attained the
    Grand Master skill level in martial arts - the player must be
    non-polymorphed - the player must have no wielded weapon - the
    player must be confused or stunned

Behavior
    The general idea is to introduce special effect attacks that
    occur during motion in an unintended direction (as when confused
    or stunned). Attacks that occur during this time will have a
    relatively high chance of producing a 'special effect' attack
    with resulting bonus damage. Additional effects would be  a
    bonus to dodge / dodging related stats during unintended motion,
    as well as a slightly higher chance of moving in the intended
    direction when confused/stunned. Each effect should be preceded
    by a regular attack, with damage applied prior to the effect
    taking place.

Effects
    - kicks - 2-4 'kicks' in a single turn
      "You deliver a flurry of sharp kicks!"

    - throw - knockback effect and falling damage
      the user displaces the monster, only works if free space
      opposite player to displace monster into "You stumble, grappling
      with %m and throwing it to the ground!"

    - theft - an attempt at stealing an item
      "Siezing an opportunity, you rifle through %m's pack!"

    - blinding - uhh, blinding effect
      "You poke %m in the eye for good measure."

    - entanglement - disrobe monster and paralyze it for 2-5 turns
    while it disentangles itself
      monster must be wearing armor, armor is removed immediately
      "You pull %m's (armor) (up/down) around its (body part)!"

    - roll - skirt past the monster to its opposite side inflicting
    some damage as you pass
      space opposite player-monster should be free for player to
      move into "You tumble past %m!"

    - corpse as weapon - if the monster is killed, you automatically
    wield its body as a weapon
      only works if you are unencumbered and the added weight would
      not encumber you small (very small) bonus chance for this to
      work against 'trices, because that would be bad ass user moves
      into space monster occupied "You catch and wield %m as it
      falls!"

STATUS:
The following effects have been implemented in a patch available at
http://www.nethacks.org...

- Kicks
- Theft
- Blinding
- Entanglement
- Corpse As Weapon (needs more testing, not sure what happens when you
  catch a cockatrice)