Switches HeroTracker to a fragment/activity pair

Current functionality of HeroTracker gets converted into the HeroDisplay fragment. New HeroTracker activity is created to host the fragment. Fixes some typos. Temporarily using automatic item import from an internal resource file until some issues
with external file loading can be worked out. Using "dumb" max vitality of 18 until equipment switching is implemented and can set it correctly. Otherwise, vitality is capped at +1 bonus from starting armor.