Do not update schematic connectivity for irrelevant property changes.

Prior to this change, the schematic connectivity was updated any time a
change was made to a connectable object.  Now the connectivity is only
updated when an object change actually affects the connectivity.  Other
properties like line width, fill type, custom fonts, etc. will not cause
the connectivity graph to be rebuilt.

The SCH_COMMIT flag SKIP_CONNECTIVITY has been removed.  All schematic
objects can test if they are connectable and if there have been changes
to any connection properties that require a connectivity rebuild.

Remove duplicate rebuild connectivity calls from editor control tool.
This was causing the tangling end test to get called four times on every
undo and redo action because the dangling end test is already called in
the connectivity graph calculation code.

Update connectivity when changing label names which fixes an unreported
connectivity bug.

eeschema/sch_commit.cpp

@@ -211,23 +211,28 @@ void SCH_COMMIT::pushSchEdit( const wxString& aMessage, int aCommitFlags )
         if( schItem->IsSelected() )
             selectedModified = true;
 
-        if( !( aCommitFlags & SKIP_CONNECTIVITY ) && schItem->IsConnectable() )
+        auto updateConnectivityFlag = [&, this]()
         {
-            dirtyConnectivity = true;
+            if( schItem->IsConnectable() )
+            {
+                dirtyConnectivity = true;
 
-            // Do a local clean up if there are any connectable objects in the commit.
-            if( connectivityCleanUp == NO_CLEANUP )
-                connectivityCleanUp = LOCAL_CLEANUP;
+                // Do a local clean up if there are any connectable objects in the commit.
+                if( connectivityCleanUp == NO_CLEANUP )
+                    connectivityCleanUp = LOCAL_CLEANUP;
 
-            // Do a full rebauild of the connectivity if there is a sheet in the commit.
-            if( schItem->Type() == SCH_SHEET_T )
-                connectivityCleanUp = GLOBAL_CLEANUP;
-        }
+                // Do a full rebauild of the connectivity if there is a sheet in the commit.
+                if( schItem->Type() == SCH_SHEET_T )
+                    connectivityCleanUp = GLOBAL_CLEANUP;
+            }
+        };
 
         switch( changeType )
         {
         case CHT_ADD:
         {
+            updateConnectivityFlag();
+
             if( !( aCommitFlags & SKIP_UNDO ) )
                 undoList.PushItem( ITEM_PICKER( screen, schItem, UNDO_REDO::NEWITEM ) );
 
@@ -250,6 +255,8 @@ void SCH_COMMIT::pushSchEdit( const wxString& aMessage, int aCommitFlags )
 
         case CHT_REMOVE:
         {
+            updateConnectivityFlag();
+
             if( !( aCommitFlags & SKIP_UNDO ) )
                 undoList.PushItem( ITEM_PICKER( screen, schItem, UNDO_REDO::DELETED ) );
 
@@ -290,6 +297,19 @@ void SCH_COMMIT::pushSchEdit( const wxString& aMessage, int aCommitFlags )
                 ITEM_PICKER itemWrapper( screen, schItem, UNDO_REDO::CHANGED );
                 wxASSERT( ent.m_copy );
                 itemWrapper.SetLink( ent.m_copy );
+
+                const SCH_ITEM* itemCopy = static_cast<const SCH_ITEM*>( ent.m_copy );
+
+                wxCHECK2( itemCopy, continue );
+
+                SCH_SHEET_PATH currentSheet;
+
+                if( frame )
+                    currentSheet = frame->GetCurrentSheet();
+
+                if( itemCopy->HasConnectivityChanges( schItem, &currentSheet ) )
+                    updateConnectivityFlag();
+
                 undoList.PushItem( itemWrapper );
                 ent.m_copy = nullptr;   // We've transferred ownership to the undo list
             }
@@ -339,7 +359,12 @@ void SCH_COMMIT::pushSchEdit( const wxString& aMessage, int aCommitFlags )
             frame->SaveCopyInUndoList( undoList, UNDO_REDO::UNSPECIFIED, false, dirtyConnectivity );
 
             if( dirtyConnectivity )
+            {
+                wxLogTrace( wxS( "CONN_PROFILE" ),
+                            wxS( "SCH_COMMIT::pushSchEdit() %s clean up connectivity rebuild." ),
+                            ( connectivityCleanUp == LOCAL_CLEANUP ) ? wxS( "local" ) : wxS( "global" ) );
                 frame->RecalculateConnections( this, connectivityCleanUp );
+            }
         }
     }