fieldsets, legends, labels in forms

The changes in this submission are:
* the file as a whole now is in UTF-8 instead of Windows codepage Cp1252 (or ISO 8859-x);
* the file now has a proper HTML5 "doctype";
* the page now has a title element (so bookmarks get a useful title, too);
* form fields have been grouped in fieldsets with legends;
* radio buttons now have labels, so you have a larger click area (you can click the label to select the radio button;
* some validation errors were correct (e.g. br elements without a > at the end).

The h2 headings are still there although they strictly speaking duplicate some of the legends in the fieldsets.