Update search classes

@tanghus, I think this should fix the problem you describe in https://github.com/owncloud/core/pull/4553#issuecomment-25425550. What I did is set up a search provider and search result as they would be set up using the updated search system; I feel that it makes it simpler to read the code and paves the way for richer search results (more properties, typed search results) while leaving the 'text' property in. Let me know what you think.

The only issue is that we can't test this until the above pull request is merged (or at least rebased); I tried and it kept on logging something like "js file not found: script:tags formfactor: serverroot:C:/Users/andrew/Code/core at C:\Users\andrew\Code\core\lib\template\resourcelocator.php#45".