mob dead state tweaks (#162)

~~well, it SHOULD make mob rotate on death, but it doesn't, i have no idea why~~

- Blocks character movement in crit/death
- rotates character ~~360noscope~~ 90 degrees to convince you it's lying down when dead

resolves #145
resolves #158
related to #115

Resources/Prototypes/Entities/Mobs.yml

@@ -56,6 +56,9 @@
     zoom: 0.5, 0.5
 
   - type: CameraRecoil
+  - type: Appearance
+    visuals:
+    - type: SpeciesVisualizer2D
 
 - type: entity
   id: MobObserver