add internal commands for cursor movement

[StatusQuo]

Hi,

inspired by http://ghisler.ch/board/viewtopic.php?t=18515 :

I suggest to add internal commands

• cm_CursorGoUp
  cm_CursorGoDown
  cm_CursorGoLeft
  cm_CursorGoRight
  
  cm_CursorScrollUp
  cm_CursorScrollDown
  cm_CursorScrollLeft
  cm_CursorScrollRight
  

for customizing cursor key behaviour globally.

*Go* should move the cursor to the next item in this direction,
*Scroll* should scroll the active window in this direction.