Move error reporting out of the NWDoc class

nw/gui/doceditor.py

@@ -446,7 +446,12 @@ class GuiDocEditor(QTextEdit):
         theItem.setParaCount(self.paraCount)
 
         self.saveCursorPosition()
-        self.nwDocument.writeDocument(docText)
+        if not self.nwDocument.writeDocument(docText):
+            self.theParent.makeAlert([
+                self.tr("Could not save document."), self.nwDocument.getError()
+            ], nwAlert.ERROR)
+            return False
+
         self.setDocumentChanged(False)
 
         self.theIndex.scanText(tHandle, docText)

nw/gui/projtree.py

@@ -528,7 +528,12 @@ class GuiProjectTree(QTreeWidget):
                         self.theParent.closeDocument()
 
                     delDoc = NWDoc(self.theProject, tHandle)
-                    delDoc.deleteDocument()
+                    if not delDoc.deleteDocument():
+                        self.makeAlert([
+                            self.tr("Could not delete document file."), delDoc.getError()
+                        ], nwAlert.ERROR)
+                        return False
+
                     self.theIndex.deleteHandle(tHandle)
                     self._deleteTreeItem(tHandle)
                     self._setTreeChanged(True)