v3.6.3: Bugfixes and zc200 interoperation

This release contains changes associated with the following GitHub issues:

#302: Correct template's template_info.php to report the current version.
#303: Update to support zc200's "Wholesale Pricing".
#304: Two trashcan icons were being displayed on the shopping_cart page when viewing on a 'small' screen.
#305: Enabling a fluid display on category listings.
#306: Updates to SNAF pages' header_php*.php files in support of zc200.
#307: Correct PHP Warnings on products' listing display order if no matching product is found.
#310: Correct display on Chrome browser's device-toolbar (used to test various devices' display).
#311: Use page-specific maximums for SNAF listings' display.
#312: Correct PHP Warning on index listing when no sort is selected.
#313: Add alpha-filter to products_all page, if enabled.
#314: Upgrade from very old version winds up missing configuration settings.