* Add native support for multi-hit badiks to MF_ENEMY.

   * MF2_FRET application and removal.
   * Flashing when flag present.
   * Bounce player back on successful damaging.
   * Add their spawnhealth to the chain.
* Reduce code duplication in P_TouchSpecialThing.
* Play with Crawla Commander a little bit as a test of its power.