Fixed variable error in wpsc-shipping/usps_20.php

The variable being tested is NOT the one being assigned the new instance of ASHTools().
Filter gateway checkout form output
Add docblocks for all functions in gateways.php
cleaning up wpsc_the_category
_title
Fix: Decimal separator are not treated correctly when saving products.

Issue #96.
Fix: Make sure Add / Edit Product page respects decimal and thousands
separators set in Settings->Store->General.
Float casting is not locale aware.
- not passing 2 params

Killing a debug notice in core by no longer passing the $id param in
core even though the_title filter provides it.
Remove all references to use-x-times and free-shipping for coupons.

These seem to be legacy references from before 3.8. No need to replicate
these features when the underlying database structure isn't there.
Use plus / minus buttons to add / remove coupon conditions. The condition fields
are also now translatable properly.
Coupon statuses are displayed as text rather than icons.
Adjust coupon condition field's width.
Fix: Adding conditions when editing coupon doesn't work.
Update messages for coupon
CSS style for datepicker
Checkbox labels should be next to the checkboxes themselves.
Fix bugs with coupon start & expiration timezone.

- Timezones are not taken into account
- Can't save start / expire time when editing coupon.
Update readme.txt.
Bump version.
Split out ShareThis JavaScript.