Don't hard code style; use class and improve CSS

This changes the hard-coded style for what I'm calling the
content-with-donate-sidebar. The advantage of not hard-coding style are
obvious, but I'm doing this now rather than later so that I can add
changes to the CSS that causes the width to extend to 100% on smaller
screen media when the donate bar disappears (the latter of which is
already implemented).

Make it abundantly clear everyone can come.

Karen got feedback that some people were confused about who can attend.
This change makes it more abundantly clear everyone can attend.

Don't list full menu on signup page.

After much discussion with Tony and tmarble, we've concluded not to put
the menu on the initial page, and instead place it on the thank-you
page, to which PayPal payers are redirected.

Close paren (HT tmarble)

<tmarble> (likely vegetarian needs closing paren [16:17]

Remove (aka Bruxelles) (per tmarble)

<tmarble> (aka Bruxelles) is not required [16:16]
<bkuhn> tmarble: removed
<bkuhn> I put it in only because people might not know.
<bkuhn> (I didn't the first year I attended)

Add supporter night button.

Thanks to Tony for making it.

No banner done for this one:

<bkuhn> tony: also, do you want a banner, ala
http://sfconservancy.org/img/conservancy-supporter-header.png ?
[16:09]
<tony> nah, this is such a short term thing. I don't think it's necessary

First pass at Supporter Night form.

This is my first pass of the supporter night form with necessary
Javascript and CSS.