Improved location support

I've been working on adding some location features to this module for a site I maintain. These are:

• Sort results by distance to a given location
• Show the distance to the given location in the search results

I've attached a screenshot of what it looks like, and will push the code to a branch in a bit. I'm after some early feedback on whether these features would be accepted or not and what the maintainers think of it generally. (I know it needs some tests written...)