Footer Improvements

[ajpiano]

The footer, as is, is pretty slim on functionality but pretty thick on actual thickness. Don't want to block the announce with it, but we should add a "supported by Bocoup" footer ala openvisconf.com as well as some supplemental navigation.

[rwaldron]

[rwaldron]

[ajpiano]

Looks much better!! Curious if anyone thinks we should have some kind of duplication of the header nav in the footer, or if it's overkill. cc @isaacdurazo @Wilto

[rwaldron]

That seems easy enough.

[rwaldron]

But I'm not sure "where", so I'm not going to fiddle around with it.