1. Improved DAO.class.php, when no results returned for "select" sql, return false;

1. Improved DAO.class.php, when no results returned for "select" sql, return false;
2. On "import/export course" page, truncate folder/content titles in the drop down list box to 65 chars;
3. Only when content type is "html", parse content and extract primary resources
4. In output.inc.php -> provide_alternative(), don't call convert_amp() on content since the plain text would not have alternatives defined.