block path and alliasses

In block.module can yoy define a path when to show a block. It's using a request_uri function to check that. But then, it fails when using aliasses. This patch will replace the request_uri with a _get[q]. Now it works with aliasses as well. I'm no hero with regex, but I tested it with the examples in the help section of the block and it works well this way.

Greetings, Nick