src/web-client/html-form.php: Make exception raised when "multiple submit buttons found on form, but no submit button specified for form submission" more helpful by listing the available buttons.
src/web-client/html-form.php: Add proper type-declaration for HtmlForm->populateFromDOMNode, and add 'TODO' comment indicating it should actually be renamed to reflect the fact it accepts a DOMElement. :P
src/webapp/filters/csrf-guard.php: Minor tweak to variable names to increase clarity.