Reworked admin tab system to allow for third-party registered tabs
Fixed tax locale uploads
Fixed item/product tax rule matching
Replaced CartTax with ShoppTax implementation
Fixed #2436 Added fix to protect loading the ShoppLoader only during direct requests
Update Customer.php

Assign result from filter to variable for message instead of appending it as a new element.
Fix for issue #2438.
Fixed collection.row behavior to ensure the first product on the first row is true
Cleaned up the language used for in progress orders on the thanks page
Fixed purchase events to use static handlers instead of instance handlers

This changeset fixes order notifications to prevent the possibility of duplicate notifications.
Refactored the checkout workflow for PayPal Standard

After submitting the order for PayPal payment, the normal confirm order process runs. Instead of again needing to click the "Checkout with PayPal" button, a redirect page is used to auto-submit the POST form to submit the order to PayPal from the client browser.

If JavaScript is disabled, graceful degradation provides another "Checkout with PayPal" submit button to submit the order for payment.

This process brings offsite payment processing much closer to the same process as onsite payments.
Updated class names with 'Shopp' prefix
Fixed #2440 ShoppCollectionPage and ShoppProductPage theme templates for better specificity
Merge pull request #2441 from ben72/patch-3

Fix for new user email notifications
Fixed #2349 Rebuilt category manager action handler
Fixed #2439 Rebuilt category manager action handler
Merge branch 'master' of code.shopp.net:core/shopp
Fixed #2443 Replaced the admin controller tabs() rendering method
Fixed PHP notice
Improved debug_caller() handling/reporting
Closed #2354 Improved authed order event locking behaviors for race conditions