There are several places in this PR that have variable array keys.  [WordPress Coding Standards](http://make.wordpress.org/core/handbook/coding-standards/php/#space-usage) dictate that when a variable is used to reference a key, it should be given some breathing room.

If we're intending to deviate from that standard, we should document that and explain why in [our own coding standards](https://github.com/wp-e-commerce/WP-e-Commerce/wiki/Coding-Standards-and-Code-Quality).