Prevent tracking links that only connect an entity to itself

No reason to link an entity to itself, also prevents an error
Most prominently this occurred from constraining a ragdoll to itself

lua/cfw/core/connectivity_sv.lua

@@ -28,6 +28,8 @@ function CFW.connect(a, b)
     -- If a link already exists, add to the link counter
     -- If not, create a new link between the two entities and resolve their contraptions
 
+    if a == b then return end -- Should not happen normally, but ragdolls allow you to constrain to other bones on the same ragdoll, and it is the same entity. We'll head it off here since we don't want to track links that don't actually link anything
+
     local link = a:GetLink(b)
 
     if link then
@@ -61,6 +63,8 @@ function CFW.connect(a, b)
 end
 
 function CFW.disconnect(entA, indexB)
+    if entA:EntIndex() == indexB then return end -- Should not happen normally, but ragdolls allow you to constrain to other bones on the same ragdoll, and it is the same entity
+
     local link              = entA._links[indexB]
     local contraptionPopped = link:Sub()