Fixed bug when parsing namespaced typehint args

There is a bug with the moodlecheck functionargs check.

It doesn't nicely parse typehints that are namespaced.
For example prior to this patch the following would trigger the check to fail.

    <?php
    // This file is part of Moodle - http://moodle.org/
    //
    // Moodle is free software: you can redistribute it and/or modify
    // it under the terms of the GNU General Public License as published by
    // the Free Software Foundation, either version 3 of the License, or
    // (at your option) any later version.
    //
    // Moodle is distributed in the hope that it will be useful,
    // but WITHOUT ANY WARRANTY; without even the implied warranty of
    // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    // GNU General Public License for more details.
    //
    // You should have received a copy of the GNU General Public License
    // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
    
    /**
     * Test script
     *
     * @package    core
     * @copyright  2013 Sam Hemelryk
     * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
     */
    
    namespace one\two {
        /**
         * Class foo
         * @copyright  2013 Sam Hemelryk
         * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
         */
        class foo {}
    }
    
    namespace three {
        /**
         * Class bar
         * @copyright  2013 Sam Hemelryk
         * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
         */
        class bar {
            /**
             * This is three.
             * @param \one\two\foo $foo
             */
            public function __construct(\one\two\foo $foo) {}
        }
    }