Initial pass at separating the profile picture from the custom header

Total rough pass, there's likely a cleaner way to do this but it works.
Moving the profile picture in to a separate setting allows the custom
header to be a larger image shown alongside content.
Revert "Initial pass at separating the profile picture from the custom header"

This reverts commit 74bb862909ef306f5442e3868ba7b73d72ab2e63.
Rough first pass at vertical custom header

Adds the ability to set a custom header and a rough set of stylesheets.
Still to come are refinements for responsive breakpoints and the
addition of the profile picture.
Cleanup of custom header styles
First pass at tablet styles for header

With the new header image the theme needs more specific responsive
styles.
Clean up header styles on tablets

First pass missed some background colors and positioning changes.