put title attributes on section/div elements in API documentation

The documentation at https://edge.launchpad.net/+apidoc/ has "id" attributes on the div elements that delimit its various sections (go to the page, do View Source, and search for "id=" to see). However, there are no corresponding "title" attributes with the same values as the "id" attrs.

If there were title attributes then -- in some browsers, at least -- one could see a section's anchor name just by hovering over that section. This would be very useful for referring someone to a specific place in the documentation.

I have a branch for this, but am still gathering enough xslt-fu to actually test it. Review welcome.

Note: bug #325367 ("the API docs should have a table of contents") is likely to involve similar knowledge.