Work around IE crumminess in context-menu code

The code that selected the content of the textarea on a right-click
wasn't selecting everything in IE because of the schizophrenic
approach it takes to newlines and carriage returns.

Author: marijnh

lib/codemirror.js

@@ -1126,7 +1126,7 @@ var CodeMirror = (function() {
         "border-width: 0; outline: none; overflow: hidden;";
       var val = input.value = getSelection();
       input.focus();
-      setSelRange(input, 0, val.length);
+      setSelRange(input, 0, input.value.length);
       if (gecko) e.stop();
       leaveInputAlone = true;
       setTimeout(function() {