textLength improvement.

README.md

@@ -487,6 +487,7 @@ parameter must be a string.
 - __getLines()__ - an array containing the content lines.
 - __getScreenLines()__ - an array containing the lines as they are displayed on
   the screen.
+- __textLength(text)__ - get a string's real length, taking into account tags.
 
 
 #### Box (from Element)

lib/widget.js

@@ -2307,7 +2307,10 @@ Element.prototype.textLength = function(text) {
   if (!this.options.tags && !this.options.parseTags) {
     return text.length;
   }
-  return text.replace(/{(\/?)([\w\-,;!#]*)}/g, '').length;
+  return text
+    .replace(/{(\/?)([\w\-,;!#]*)}/g, '')
+    .replace(/\x1b\[[\d;]*m/g, '')
+    .length;
 };
 
 // Convert `{red-fg}foo{/red-fg}` to `\x1b[31mfoo\x1b[39m`.