Editing js to affix the footer and size the header

Previously these were two different "script" elements that both defined
window.onload and a window.onresize functions. However, this meant that
the scripts could not both run. A new function that is a wrapper for these
two was added to address this problem. There are still lag issues though,
and the onload script does not seem to work for the header image -- it
defaults to the CSS defined height.
Update sizeHeader js to match the page breakpoints

Now there are two sizes for the large banner before it takes up the entire
window height. Before, there was only one smaller size and the breakpoint
was set to 599px wide.
Hide link-to-content for widths smaller than 480px