no quantity value displayed in cart

Issue Summary

In the 'view cart' block and on the 'cart' page, no quantity amount is displayed, and in case of the latter, it's not possible to alter it.

For the 'view cart' block, I can see the donation product in the list, but it appears as ' x donation $10'. On the 'cart' page, I can have more than one quantity for the same donation, e.g. 2 donations of $10. This means on the cart page I see a textfield containing $10 but a total displaying $20, and since the quantity is not displayed, it's not obvious that I've added the item twice. In addition, I can't edit the quantity like I can for other products, which means I have to remove the product entirely and then re-add it with the correct number of donations.

The attached patch fixes this by changing the hidden quantity field to be a textfield like regular products.

Cheers,
Stella