Added page up and page down key support.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@3862 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/grid.h

@@ -475,6 +475,8 @@ class wxGrid : public wxPanel
     bool MoveCursorDown();
     bool MoveCursorLeft();
     bool MoveCursorRight();
+    bool MovePageDown();
+    bool MovePageUp();
     bool MoveCursorUpBlock();
     bool MoveCursorDownBlock();
     bool MoveCursorLeftBlock();