Properly associate labels in the registration form

[afercia]

The tickets registration form is, often, one of the first WordPress-related things new WordCamp attendees use when they plan to attend a WordCamp. It's sort of a welcoming, warm "hello" the WordPress community reserves for new contributors.

Unfortunately, the form is not fully accessible. It would be great to give a warm welcome also to users who use a keyboard or a screen reader, to help them fill the form without barriers.

Specifically, all the form field "labels" are not real <label> elements. They're just text wrapped inside a span, and a table is used for layout.

At the very least, I'd propose to give each field a <label> element, explicitly associated with for/id attributes (not wrapping the field) as recommended by the WordPress accessibility coding standards.

Optionally, but not strictly necessary, it would be nice to remove the table used for layout and use just CSS 🙂

To test, check any incoming WordCamp web site, for example:
https://2017.dc.wordcamp.org/tickets/
(more on https://central.wordcamp.org/schedule/)
select one ticket and press "Register" to access the registration form.

[EugenioPetulla]

I started investigating on this during WordCamp torino with @afercia but after I found this pull request that seems perfect to solve this issue: #196

Is there a chance that someone will review and merge this pull request?