Filter gateway checkout form output
Add docblocks for all functions in gateways.php
Fix instances of "siteurl" that should use home_url().
Remove unused  $siteurl references.
Use site_url() instead of get_option( 'siteurl' ).
Use admin_url() instead of "siteurl" for admin URLs.
home_url() should include slash when adding query args. Props meloniq
Use get_edit_post_link() for product edit link. Props meloniq
move payment gateway settings inline, removing the settings sidebar.
render list of payment gateways more similar to the wordpress plugins page.
improve handling of display names for payment gateways
add current display name to payment gateway table. improve cancel button on payment gateway settings rows.
improve layout of settings form and buttons in payment gateways table
Added filters to the rates in the usps shipping

Added two filters for both International and Domestic shipping rates so plugins can hook them and apply any additional fees, etc. without altering the WP-e-Commerce core code.
registration.php has been deprecated since WP 3.1
Remove context filter, it breaks stuff in WP 3.5 w/ WP_DEBUG on

Props benhuson
Update colorbox.js to V1.4.15
Re-code product thumbnail functions to prioritise use of post thumbnail if available to reduce unnecessary requests.
Don't blame Cameron :)
Remove hype from readme.txt