Include warning about limited results on search page

In the search page, users can only browse up to 10.000 results. The interface could be clearer that the "last page" does not actually contain the final results.

Suggestion: show a warning message if you visit page 500 and there are more than 10.000 results total. E.g. "Your query has X results, but only the first 10.000 results can be browsed on Textcavator."
