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/gui/DatabaseWidget.h

@@ -83,6 +83,7 @@ public:
     DatabaseWidget::Mode currentMode() const;
     bool isLocked() const;
     bool isSaving() const;
+    bool isSorted() const;
     bool isSearchActive() const;
     bool isEntryViewActive() const;
     bool isEntryEditActive() const;
@@ -99,6 +100,7 @@ public:
     bool isGroupSelected() const;
     bool isRecycleBinSelected() const;
     int numberOfSelectedEntries() const;
+    int currentEntryIndex() const;
 
     QStringList customEntryAttributes() const;
     bool isEditWidgetModified() const;
@@ -167,6 +169,8 @@ public slots:
     void deleteEntries(QList<Entry*> entries);
     void focusOnEntries();
     void focusOnGroups();
+    void moveEntryUp();
+    void moveEntryDown();
     void copyTitle();
     void copyUsername();
     void copyPassword();