agree to -> shall

MSCD 3.83-3.85 recommends using "shall" instead of "agree to" for what it calls "language of obligation", so I have removed two instances of "agree to".

Again, MSCD's categories of contract language (obligation, the previously mentioned "performance", and others) are to me MSCD's most useful mental discipline, because they help me think through exactly what I want a given clause to do, and then they give me the right language to do it with.