Need to be able to cart item image customization on shopping cart page.
Using a filter just as is done in wpsc_cart_item_url() would be
consistent.

Issue #148
- working through docs
ignoring PHPstorm files
more docs
- finished docs on the file
- lining up with WordPress coding standards

Switched to tabs for beginning of line and spaces mid line which is what
the WordPress coding standards want.
working through documenting the admin.php file
cleaned up formatting more so it all matches
removed terminating ?> since it is not needed
making it further in the docs for admin.php
finished docs on admin.php file
updating with changes from garyc40 notes
another pass at the docs bringing it all in line better with WP
standards
docs for ajax-and-init-php
touching up the function docs
docs on wpsc-admin/ajax.php
starting docs on the debug page
removing terminating php tags
documentation for short code functions

Added docs for the short code functions and removed the terminating ?> php tag.