ACTION-2053: Draft-y language for Accessibility Considerations sections

Here is some drafty language.  This might need to be tuned for the various
specifications that we are looking at, but it is a starting point.

N.N. Accessibility Considerations

This specification has no defined user interface.  Consequently, there are
no specific accessibility requirements on implementations. However, to the
extent that an implementation provides user interactions to support this
specification, the implementation must ensure that interface is exposed to
the platform accessibility API.  Moreover, implementors should take into
consideration the needs or their users with varying abilities when
designing solutions that support this specification. For example, the use
of biometric authentication techniques should be varied enough to allow for
people with widely different physical abilities.

P.S.  Note that this came up in the Payments Accessibility meeting today
too,  The Browser Payment API spec and the Payment Application spec will
both need language like this.

-- 
Shane McCarron
Projects Manager, Spec-Ops