Cleanup of JS/CSS files; Fixes #34 (order-page ad)

Begins normalizing the directory structure and naming pattern of
clientside resource files (javascript and CSS files); Removes unused
scripts and stylesheets; create "Dir" class for file iteration; Fixes
#34 by pulling advert images dynamically from a specified directory
("home1/ppp/public_html/pppv2/_/img/order-page-ads")