Updated package to latest version, 3.6.0. Changes include:
  * Improves and simplify the wrapping interface. Breaking change.
  * Add the possibility to specify converters, for constants functions.
    See also eliom's shared react.
  * Fix printing of floating numbers.
  * Add the main element.
  * Fix the accept attribute.
  * Add Tyxml_name, which allows to derive tyxml identifiers from HTML
    elements and attributes.
  * Internally build the tool `autoname`, which applies the aftermentionned
    transformation for the given elements/attributes.
  * Fix typo in `datetime-local`.
  * Add download attributes for area and tags.
  * Add various svg `text` attributes.
  * Fix namespaces issues related to svg elements inside html.
  * Add `a_lang` for HTML. Deprecate `a_srclang` in favor of `a_xml_lang`.
  * Fix a performance issue with `Xml_print.Utf8.{normalize, normalize_html}.
  * Remove `Xml_print.Utf8.normalize_from`.
    The function was not useful and not optimizable easily.
  * Add missing parameters for the attributes xlink:actuate and xml:space.
  * Svg elements use the xlink namespace (contribution by Florent Becker).
  * Do not use the `url(...)` form when inappropriate (contribution by Florent Becker).
  * Fix a typo in the `spellcheck` attribute (contribution by Kevin Brubeck Unhammer).
  * Fix the `sizes` attributes and add missing attributes for the `sandbox` tag (contributions by Eyy端b Sari).
  * Fix the `img` tag in the syntax extension.
  * Fix compilation of the opam package under freeBSD.
  * Fix typing for the various `font_` svg attributes.

(jaapb)