GUI and code tweaks and fixes (#852)

* Improve format menu header descriptions
* Ensure that item status is parsed after item class from XML
* Fix column alignment in ToC.txt file
* Rename test variable and fix outdated docstring
* Fix ToC.txt underline
* Rename the Layout label on the item details panel
* Add option to emphasise H1 and H2 labels in the project tree
* Rename the main column of the novel tree to match project tree
* Use the same document icons in the outline as the project tree
* Move project tree settings to Project section of config file

nw/tools/writingstats.py

@@ -502,9 +502,7 @@ class GuiWritingStats(QDialog):
     ##
 
     def _updateListBox(self):
-        """Load/reload the content of the list box. The dummyVar
-        variable captures the variable sent from the widgets connecting
-        to it and discards it.
+        """Load/reload the content of the list box.
         """
         self.listBox.clear()
         self.timeFilter = 0.0