Add support for checking against $_GET(in addition to $_REQUEST)

[eigood]

What problem does this address?

I'm using FormidablePro, and it has the ability to send email confirmations. It takes the submitted form data, and places it into $_GET. However, this plugin(via includes/frontend/visibility-tests/query-string.php, only checks against $_REQUEST, so never sees any values to test against. I'm also using [urlparam], and it correctly checks for $_GET, but would much prefer to use the block gui to configure things.

What is your proposed solution?

I'm not sure if changing that file to use $_GET is correct, or if a separate test should be added.