Implemented keyboard selection and better cell navigation for tables

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76440 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/richtext/richtextctrl.h

@@ -1977,6 +1977,16 @@ public:
     */
     virtual bool ExtendSelection(long oldPosition, long newPosition, int flags);
 
+    /**
+        Extends a table selection in the given direction.
+    */
+    virtual bool ExtendCellSelection(wxRichTextTable* table, int noRowSteps, int noColSteps);
+
+    /**
+        Starts selecting table cells.
+    */
+    virtual bool StartCellSelection(wxRichTextTable* table, wxRichTextParagraphLayoutBox* newCell);
+
     /**
         Scrolls @a position into view. This function takes a caret position.
     */