Restructure, images for docs, make output more configurable

Makefile

assets/download_medium.png

assets/download_small.png

assets/downloads_for_sale.css

assets/index.html

downloads_for_sale.php

downloads_for_sale.script.php

downloads_for_sale.xml

downloads_for_sale/tmpl/index.html

downloads_for_sale/tmpl/order_compact.php

downloads_for_sale/tmpl/order_image.php

downloads_for_sale/tmpl/order_long.php

downloads_for_sale/tmpl/order_text.php

downloads_for_sale/tmpl/product_compact.php

downloads_for_sale/tmpl/product_long.php

en-GB.plg_vmcustom_downloads_for_sale.ini

en-GB.plg_vmcustom_downloads_for_sale.sys.ini

images/downloads_for_sale_-_customfield_new.png

images/downloads_for_sale_-_customfields.png

images/downloads_for_sale_-_icon.png