Initial inline docs for ajax.functions.php

Initial inline docs created.
Initial admin-form-functions.php inline docs
Fixing @package for purchase-log-action-links.php

Updating docs
How about a change in default placeholder?

I sort've noticed this on the products creation page. I think it would be a neat little thing to do.
"Enter product title here" lowercase fix

In wpsc-functions.php
Merge pull request #1651 from NikV/master

Small Inline Docs (Pass 1) by NikV