Add documentation for dimension and weight unit functions.
Added 'wpsc_product_min_cart_quantity' filter.
Fix the product excerpt not to return the additional product details.
Merge pull request #532 from benhuson/default_units_docs

Add documentation for dimension and weight unit functions.
Merge pull request #540 from benhuson/minimum_order_qty

Added 'wpsc_product_min_cart_quantity' filter.
Merge pull request #535 from benhuson/get_the_excerpt

Fix the product excerpt not to return the additional product details.
Merge pull request #536 from JeffSparkleGear/Custom-Meta-Init

Replicated logic from custom meta functions
Allow gateway setting forms to be methods of a class
Merge pull request #542 from leewillis77/merchant_api_fix

Allow gateway setting forms to be methods of a class
Bump 3.8.13 version
fix empty image tag

also fixes flood of php warnings like these:
PHP Notice:  Use of undefined constant HEADER_IMAGE_WIDTH - assumed
'HEADER_IMAGE_WIDTH' in
/home/pyebrook/pyebrook.com/wp-content/plugins/WP-e-Commerce/wpsc-components/theme-engine-v1/helpers/page.php
on line 1237
PHP Notice:  Use of undefined constant HEADER_IMAGE_HEIGHT - assumed
'HEADER_IMAGE_HEIGHT' in
/home/pyebrook/pyebrook.com/wp-content/plugins/WP-e-Commerce/wpsc-components/theme-engine-v1/helpers/page.php
on line 1237
Merge branch 'master' of github.com:wp-e-commerce/WP-e-Commerce into fix-empty-image-tag
Merge branch 'fix-empty-image-tag' into local.master