SoTD is missing standard "can change from under you" warning

[marcoscaceres]

We need to add the old disclaimer:

Implementors should be aware that this specification is not stable. Implementors who are not taking part in the discussions are likely to find the specification changing out from under them in incompatible ways. Vendors interested in implementing this specification before it eventually reaches the Candidate Recommendation stage should join the aforementioned mailing lists and take part in the discussions.

The missing text is one of the reasons Respec is complaining in bug #67

[mounirlamouri]

We are missing a <section id='sotd'> I believe.