themes: MDL-19077 new $OUTPUT->header/footer to replace print_header/footer.

Also, part of the change from weblib.php functions to $OUTPUT-> methods.

This is part of http://docs.moodle.org/en/Development:Theme_engines_for_Moodle%3F

This is a big change, and the result is not perfect yet. Expect some debugging output
on some pages.

The main part of these changes are that $OUTPUT->header now looks for a file
in the theme called layout.php, rather than header.html and footer.html. Also
you can have special templates for certain pages like layout-home.php. There is
fallback code for Moodle 1.9 themes, so they still work.

A few of the old arguments to print_header are no longer supported. (You get an
exception if you try to use them.) Sam H will be cleaning those up.

All the weblib functions that have been replaced with $OUTPUT-> have version in
deprecatedlib, so existing code will go on working for the foreseeable future.

lib/javascript-static.js

@@ -1029,4 +1029,15 @@ function hide_item(itemid) {
     if (item) {
         item.style.display = "none";
     }
+}
+
+/**
+ * Tranfer keyboard focus to the HTML element with the given id, if it exists.
+ * @param controlid the control id.
+ */
+function focuscontrol(controlid) {
+    var control = document.getElementById(controlid);
+    if (control) {
+        control.focus();
+    }
 }