[bug] s_filtergrid.cu does not compile missing thrust/host_vector.h header

[dagata-mining]

When building popsift latest version on ubuntu 20.04
s_filtergrid.cu misses a header and cannot find host_vector
Please add to header
#include <thrust/host_vector.h>

[simogasp]

at some point it will be fixed by #133

[simogasp]

fixed by #144