Move investigator counter object to on-demand retrieval

src/core/PlayArea.ttslua

@@ -8,7 +8,7 @@ DEBUG = false
 -- we use this to turn off collision handling until onLoad() is complete
 COLLISION_ENABLED = false
 
-local investigatorCounter = getObjectFromGUID('f182ee')
+local INVESTIGATOR_COUNTER_GUID = "f182ee"
 local clueData = {}
 spawnedLocationGUIDs = {}
 
@@ -123,5 +123,6 @@ function onCollisionEnter(collision_info)
 end
 
 function getInvestigatorCount()
+  local investigatorCounter = getObjectFromGUID('f182ee')
   return investigatorCounter.getVar("val")
 end