Disable auto-scroll and make overflow-x hidden when soft-wrap is enabled

src/atom/cursor.coffee

@@ -128,7 +128,9 @@ class Cursor extends View
       @editor.scrollTop(desiredTop)
 
   autoScrollHorizontally: (position) ->
-    charsInView = @editor.lines.width() / @width()
+    return if @editor.softWrap
+
+    charsInView = @editor.width() / @width()
     maxScrollMargin = Math.floor((charsInView - 1) / 2)
     scrollMargin = Math.min(@editor.hScrollMargin, maxScrollMargin)
     margin = scrollMargin * @width()

src/atom/editor.coffee

@@ -230,10 +230,13 @@ class Editor extends View
   setSoftWrap: (@softWrap) ->
     @setMaxLineLength()
     if @softWrap
+      @addClass 'soft-wrap'
       @_setMaxLineLength = => @setMaxLineLength()
       $(window).on 'resize', @_setMaxLineLength
     else
       $(window).off 'resize', @_setMaxLineLength
+      @removeClass 'soft-wrap'
+
 
   clipScreenPosition: (screenPosition, options={}) ->
     @renderer.clipScreenPosition(screenPosition, options)