This adds to Zulip support for a user changing their own email
address.
It's backed by a huge amount of work by Steve Howell on making email
changes actually work from a UI perspective.
Fixes#734.
This re-adds the deleted "Delete Avatar" button back to the
settings/your-account tab view in the overlay, which only appears
if you do not currently have a gravitar.
This is technically part of the settings page redesign in the next
commit, but it's probably useful to keep separate, since it touches
totally different code.
There was a duplicate #full_name ID being added many times in tables.
They should be removed because they are not being called anywhere and
should not exist in multiples.
The data-name attribute in this case allows for a particular settings
section element to show up when the appropriate sidebar category is
clicked (which will have the same value in the data-section key).