Update TSC membership list.
Update TSC membership list.

Per the TSC meeting of 2015-09-16, Michael and Steven move to observer
status to honor the 25% rule after IBM's acquisition of StrongLoop.

nodejs/new.nodejs.org,phillipj/new.nodejs.org,marocchino/new.nodejs.org,yous/new.nodejs.org,abdelrahmansaeedhassan/yuri,boneskull/new.nodejs.org,wonderdogone/new.nodejs.org,abdelrahmansaeedhassan/yuri,rnsloan/new.nodejs.org,boneskull/new.nodejs.org,strawbrary/nodejs.org,nodejs/new.nodejs.org,wonderdogone/new.nodejs.org,strawbrary/nodejs.org,marocchino/new.nodejs.org,matthewloring/new.nodejs.org,rnsloan/new.nodejs.org,yous/new.nodejs.org,matthewloring/new.nodejs.org,phillipj/new.nodejs.org