Fix: Making it possible to redirect to the menu where users choose a page type for their new page

(edit) Old title: Fix: Default page type when adding a new page
(edit) See second comment for details on the new more elaborate fix.

Currently the page creation page fails to load if no page type is specified.

This is an issue because users can get redirected to the creation page without such a page type being specified.

One occasion where this happens is when they try to edit a page that does not exist (line 350): <pre>		// Got page?
		if ( ! $page or empty($page))
		{
			// Maybe you would like to create one?
			$this->session->set_flashdata('error', lang('pages:page_not_found_error'));
			redirect('admin/pages/create');
		}</pre>

The proposed fix in case of missing page_type input simply selects the first row from the page_type table - avoiding the assumption that no one will delete the default page_type.