Add natural sort of entry list

Introduce a third unsorted status that shows entries in the order they occur in the KDBX file.

* Add keyboard shortcut Ctrl+Alt+Up/Down to move entries up and down in sort order
* Add entry context menu icons to achieve movement up/down
* Only show menu icons when in natural sort order
* Add Material Design icons for moving up/down

* Add feature to track non-data changes and force a save on exit to ensure they are not lost when locking a database. This allows users to make entry movements and group expand/collapse operations and not lose that state.

Remove saveas

src/core/Entry.h

@@ -233,6 +233,9 @@ public:
     void beginUpdate();
     bool endUpdate();
 
+    void moveUp();
+    void moveDown();
+
     Group* group();
     const Group* group() const;
     void setGroup(Group* group);