clamp `num_features_to_query` to `1...max` range (at least one feature will queried) + use `std::size_t` for feature count (ref #3515)
clamp `num_features_to_query` to `1...max` range (at least one feature will queried) + use `std::size_t` for feature count (ref #3515)

lightmare/mapnik,CartoDB/mapnik,tomhughes/mapnik,mapycz/mapnik,mapnik/mapnik,mapnik/mapnik,CartoDB/mapnik,tomhughes/mapnik,mapycz/mapnik,naturalatlas/mapnik,mapnik/mapnik,naturalatlas/mapnik,CartoDB/mapnik,mapnik/mapnik,lightmare/mapnik,naturalatlas/mapnik,tomhughes/mapnik,lightmare/mapnik,lightmare/mapnik,tomhughes/mapnik,mapycz/mapnik,naturalatlas/mapnik