Rename search variable from @results to @search. Clearer I think.
Refactor to move parsing logic into ResultSet and bug fix

* Moved XML parsing logic into ResultSet
* Fixed issue where passing a nil per_page into the query meant we
  don't get told the per page size back in our results, so we now send
  our default page size if it's nil
* Renamed some of the attributes on ResultSet to make object easier to
  use with will_paginate
Merge pull request #7 from cosm/nil_params

Fix nil per_page issue + a bit of a refactor of parsing logic