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

Content.Shared/GameObjects/Components/Mobs/SharedSpeciesComponent.cs

@@ -0,0 +1,34 @@
+using System;
+using SS14.Shared.GameObjects;
+using SS14.Shared.Serialization;
+
+namespace Content.Shared.GameObjects.Components.Mobs
+{
+    public abstract class SharedSpeciesComponent : Component
+    {
+        public sealed override string Name => "Species";
+
+        public override uint? NetID => ContentNetIDs.SPECIES;
+
+        [Serializable, NetSerializable]
+        public enum MobVisuals
+        {
+            RotationState
+        }
+
+        [Serializable, NetSerializable]
+        public enum MobState
+        {
+            /// <summary>
+            ///     Mob is standing up
+            /// </summary>
+            Stand,
+
+            /// <summary>
+            ///     Mob is laying down
+            /// </summary>
+            Down,
+        }
+  
+    }
+}