v0.5.1 — hotfix: the mouse no longer hijacks the overlays

Fixed

• The mouse no longer hijacks overlays and examine during keyboard play. The
  game quietly used the physical mouse position as its attention point: held L
  drew line of sight from the tile under the pointer (wherever it happened to
  rest), held highlight keys examined that tile every frame — narrowing the threat
  overlay to whatever unit the mouse sat on, with no keyboard way out — and any
  pointer drift moved the Look cursor. Now whichever device acted last owns the
  attention point: any keypress mutes the mouse; a mouse click or wheel wakes it
  (the waking click only wakes — the next one acts). Mouse motion alone never
  takes control, so desk bumps and screen-reader pointer routing can't steal it.
  With the keyboard in charge, held L draws from the deploy target, your
  Look/targeting cursor (a handy visual cursor tracker), or your wizard. New
  setting mouse_attention_arbitration (default true); set false for fully
  native mouse behavior.