Enhancing the [order-subtotal] token to drop the theming

I needed the order subtotal without the '$' sign, but the problem was that the default implementation of [order-subtotal] was themed, so it was rendered like '$12.20'. I just needed the value, like '12.20'.

I tweaked the uc_order.module to add a [order-subtotal-value] token, which is the same as the [order-subtotal], but it just doesn't pass thru the theming routines in uc_price.

Attached is a patch.