Strike non-refundable membership fees from bylaws

The distinction between "membership fee" (non-refundable) and
"membership" (refundable) was confusing. Since we don't intend to charge
an administrative membership fee for joining, we will remove all mention
of it from the bylaws.

As approved by the board on 2013-06-26.
Reconcile record dates for notice and voting

To save the trouble of compiling separate member lists for notice and
for voting, make the record date for notice the same as the record date
for voting (20 days).

As approved by the board on 2013-06-26.