Scrolling improvements.

[crwilliams]

Alter the scrolling to allow the site to work on smaller screen heights.

Rather than enclose the main content in a container with scrollbars, allow the whole page to scroll (perhaps with some fixed position elements).

[crwilliams]

This is proving to be difficult, given the CSS tricks that were used to center the page content. Perhaps need to reconsider screen width issues.