[expr.delete] Move footnote to more appropriate place.

Fixes #314.
[support.initlist] Don't claim that std::initializer_list is a type; it's a
class template.

Fixes #280.
[bind] Delete the essentially-empty [bind] subclause and move its only
contents, [func.bind], up a level. This removes the existing 20.9.9 and renames
20.9.9.1 to 20.9.9. [bind] used to group together other binders, but those
are now in [depr].

Fixes #284.