stress concentration

nail gun tech: stress concentration - if a mob has below 50% durability after taking damage
  from needles or rivets near the center of it's body it dies

caliber 16->25% nail, needle, rivet size/damage
combined tech: flagella - spores move +50% faster
  spores follow you if they can't find a target
shock wave stun also applies to sporangium
  no longer reduces explosion size

JUNK tech: reincarnation - kill all mobs and spawn new ones
  (also spawn a few extra mobs for fun)

updated pause menu and fields descriptions to new wording style

bug fixes

js/simulation.js

@@ -105,6 +105,7 @@ const simulation = {
         simulation.isTimeSkipping = true;
         for (let i = 0; i < cycles; i++) {
             simulation.cycle++;
+            // m.walk_cycle += (m.flipLegs * m.Vx) * 0.5; //makes the legs look like they are moving fast  (it's times 0.5 because when they move too fast it's a blur)
             simulation.gravity();
             Engine.update(engine, simulation.delta);
             // level.custom();