[active-line addon] Don't highlight line(s) with a selection.

This fixes non-empty selections having 2 highlights: the selection highlight
and the active-line highlight. Non-empty selections should only have the
selection highlight.

addon/selection/active-line.js

@@ -49,7 +49,9 @@
   function updateActiveLines(cm, ranges) {
     var active = [];
     for (var i = 0; i < ranges.length; i++) {
-      var line = cm.getLineHandleVisualStart(ranges[i].head.line);
+      var range = ranges[i];
+      if (!range.empty()) continue;
+      var line = cm.getLineHandleVisualStart(range.head.line);
       if (active[active.length - 1] != line) active.push(line);
     }
     if (sameArray(cm.state.activeLines, active)) return;