Disable automatic filtering on Google Search for more predictable result count

This addresses the issue whereby some queries would suddenly after paging through the first few pages of results suddenly present you with a greatly reduced total results count.

Disabling Google's [automatic filtering](https://developers.google.com/custom-search/docs/xml_results#automaticFiltering) seems to stop this happening.

FAO @ajitkrishnan @andrewgarner @amansinghb