Fix bing engine results count (#1387)

This PR fixes the result count from bing which was throwing an (hidden) error and add a validation to avoid reading more results than avalaible.

For example :
If there is 100 results from some search and we try to get results from 120 to 130, Bing will send back the results from 0 to 10 and no error. If we compare results count with the first parameter of the request we can avoid this "invalid" results.