Adds style to public 404, 422, and 500 pages.

Inserted scholar_uc images into public folder.
Modified .html pages to include UC Navbar.
Customized error messages on page.
Included css and javascript into <head> to make Navbar function.
Merge pull request #208 from uclibs/feature/#181_custom_error_page

Adds style to public 404, 422, and 500 pages.