Prevent autoscrolling scroll-view when cursor is at end of longest line

If the longest line is longer than the width of the scroll view, we need
to allow 2px horizontally to prevent the hidden input from
autoscrolling.

src/editor-scroll-view-component.coffee

@@ -169,6 +169,7 @@ EditorScrollViewComponent = React.createClass
     return {top: 0, left: 0} unless @isMounted() and focused and editor.getCursor()?
 
     {top, left, height, width} = editor.getCursor().getPixelRect()
+    width = 2 if width is 0 # Prevent autoscroll at the end of longest line
     top -= editor.getScrollTop()
     left -= editor.getScrollLeft()
     top = Math.max(0, Math.min(editor.getHeight() - height, top))