New translations into Spanish

Thanks to the Spanish Translation Team, Spanish Translation US, the following articles have been translated into Spanish.

Uso de entidades de caracteres y NCR (Using character entities and NCRs)
http://www.w3.org/International/questions/qa-escapes.es.php

Set de caracteres para documentos (Document character set)
http://www.w3.org/International/questions/qa-doc-charset.es.php

Cómo cambiar la codificación de la página (X)HTML a UTF-8 (Changing (X)HTML page encoding to UTF-8)
http://www.w3.org/International/questions/qa-changing-encoding.es.php