Reimplement scrolling the display up and down using the keyboard. This is now done in the display rather than the emulation, which allows displays on the same session to be scrolled independantly, but doesn't respect the scroll commands defined in the key bindings file.

svn path=/trunk/KDE/kdebase/apps/konsole/; revision=666607

src/ScreenWindow.cpp

@@ -142,6 +142,9 @@ void ScreenWindow::scrollBy( RelativeScrollMode mode , int amount )
 
 void ScreenWindow::scrollTo( int line )
 {
+    if ( line < 0 )
+       line = 0;
+
     if ( (lineCount() - windowLines()) < line )
        line = qMax(0,lineCount() - windowLines());