Turn off incremental connectivity for small schematics

The benefit of incremental connectivity is only for larger
schematics.  For smaller schematics, the downside of larger bug surface
outweighs the current benefits

eeschema/connection_graph.h

@@ -472,6 +472,18 @@ public:
     */
     void ExchangeItem( SCH_ITEM* aOldItem, SCH_ITEM* aNewItem );
 
+    /**
+     * We modify how we handle the connectivity graph for small graphs vs large
+     * graphs.  Partially this is to avoid unneeded complexity for small graphs,
+     * where the performance of the graph is not a concern.  This is considered
+     * a temporary solution until the connectivity graph is refactored with an
+     * eye toward partial updates
+    */
+    bool IsMinor() const
+    {
+        return m_items.size() < 10000;
+    }
+
 private:
     /**
      * Update the graphical connectivity between items (i.e. where they touch)

eeschema/sch_edit_frame.cpp

@@ -1779,7 +1779,7 @@ void SCH_EDIT_FRAME::RecalculateConnections( SCH_COMMIT* aCommit, SCH_CLEANUP_FL
             };
 
     if( !ADVANCED_CFG::GetCfg().m_IncrementalConnectivity || aCleanupFlags == GLOBAL_CLEANUP
-            || m_undoList.m_CommandsList.empty() )
+            || m_undoList.m_CommandsList.empty()|| Schematic().ConnectionGraph()->IsMinor() )
     {
         // Update all rule areas so we can cascade implied connectivity changes
         std::unordered_set<SCH_SCREEN*> all_screens;