add required thrust include for s_filtergrid.cu

Author: Azhng

src/popsift/s_filtergrid.cu

@@ -19,9 +19,11 @@
 #if ! POPSIFT_IS_DEFINED(POPSIFT_DISABLE_GRID_FILTER)
 
 #include <thrust/copy.h>
+#include <thrust/count.h>
 #include <thrust/device_vector.h>
 #include <thrust/execution_policy.h>
 #include <thrust/host_vector.h>
+#include <thrust/iterator/constant_iterator.h>
 #include <thrust/iterator/discard_iterator.h>
 #include <thrust/sequence.h>
 #include <thrust/sort.h>