Rename open and save document to read and write in NWDoc

nw/dialogs/docmerge.py

@@ -110,8 +110,9 @@ class GuiDocMerge(QDialog):
         theDoc = NWDoc(self.theProject, self.theParent)
         theText = ""
         for tHandle in finalOrder:
-            theText += theDoc.openDocument(tHandle, False).rstrip("\n")
-            theText += "\n\n"
+            docText = theDoc.readDocument(tHandle, False).rstrip("\n")
+            if docText:
+                theText += docText+"\n\n"
 
         if self.sourceItem is None:
             self.theParent.makeAlert(
@@ -130,8 +131,8 @@ class GuiDocMerge(QDialog):
         newItem = self.theProject.projTree[nHandle]
         newItem.setStatus(srcItem.itemStatus)
 
-        theDoc.openDocument(nHandle, False)
-        theDoc.saveDocument(theText)
+        theDoc.readDocument(nHandle, False)
+        theDoc.writeDocument(theText)
         self.theParent.treeView.revealNewTreeItem(nHandle)
         self.theParent.openDocument(nHandle, doScroll=True)