MDL-21652 html_table rendering refactored

* class html_component does not exist any more
* class html_table rendered via html_writer::table()
* html_table, html_table_row and html_table_cell have public $attributes property to set their CSS classes
* dropped rotateheaders feature, should be added again after more research of possible ways (<svg> is not nice IMHO)
* dropped possibility to define CSS classes for table heading, body and footer - can be easily done and better done using just table class and context

mod/survey/view.php

@@ -115,7 +115,7 @@
                         $table->head = array(get_string($question->text, "survey"));
                         $table->align = array ("left");
                         $table->data[] = array(s($answer->answer1));//no html here, just plain text
-                        echo $OUTPUT->table($table);
+                        echo html_writer::table($table);
                         echo $OUTPUT->spacer(clone($spacer)) . '<br />';
                     }
                 }