Adding filter and hook for subtotals

Signed-off-by: Zane M. Kolnik <zanematthew@gmail.com>
Adding check for empty cart in session.

Signed-off-by: Zane M. Kolnik <zanematthew@gmail.com>
Incorrect variable name causing sizes not to show, #471.

Signed-off-by: Zane M. Kolnik <zanematthew@gmail.com>
Adding filter for total and debug code

Signed-off-by: Zane M. Kolnik <zanematthew@gmail.com>
Removing debug code.

Signed-off-by: Zane M. Kolnik <zanematthew@gmail.com>
Removing download link for reprint only items, #469

Signed-off-by: Zane M. Kolnik <zanematthew@gmail.com>
Removing download links for reprint items on the thanks page and download list page, #469
Change log updates

Signed-off-by: Zane M. Kolnik <zanematthew@gmail.com>