Use more HTML in the membership update form

[adehnert]

The membership update form (​https://asa.mit.edu:444/membership/update/2012-fall/32/) has a bunch of text. It should take advantage of HTML existing to be a little easier to read:

• Link each of the four components at the top to the corresponding explanatory section
• Link "The text of the law is at the bottom of this page." to the corresponding part of the page
• Possibly group the four numbered sections into "Process" or "Stages" or something, make that an h2, and demote the rest to h3

[adehnert]

Fixed:

commit bcd1b62f3f9c32a3a32514ecc55909b8fa49e190
Author: Alex Dehnert <adehnert@mit.edu>
Date:   Tue Nov 13 05:15:24 2012 -0500

    Membership update: reformat and proofread
    
    Reformat the membership update page to be easier to read (ASA-#177) and fix
    some grammatical issues (ASA-#178).