Adding CSS selectors into the purchase page.

Table level:
#act-purchase:  Describes the entire purchase table.
Row level:
.act-product: Each table row containing product information.
.act-price: Each table row containing product pricing information.
.act-donation: Table row prompting for a donation
.act-purchase-submit:  Bottom row containing the buy now button.
Table cells:
.act-select: Table cell containing radio button or checkbox.
.act-description: Table cell describing the product or price.
.act-amount:  Table cell describing the cost.
.act-currency:  Table cell describing the cost currency.
Merge pull request #48 from dwright/master

Adding CSS selectors into the purchase page.