angband: Update to 4.2.1

  Summary of Changes

    * percentage combat is refined to become an actually playable option
    * improvements to throwing
    * udate to town generation
    * a major update to the new blackguard class
    * several tweaks to the other new classes
    * many improvements to the MacOS front-end particularly, but also others
    * improvements to tiles
    * addition of fancy color-cycling of monsters
    * configurability of charecter sheet
    * inclusion of some new, rare level types
    * experimental Windows curses and SDL2 console ports added
    * many small bugs fixed and quality-of-life improvements made

(nia)