Don't need <thrust/extrema.h> as more specific <thrust/detail/minmax.h>
is already included providing thrust::min.
Merge branch '1.7.2'
Use stream inside CUDA reduce implementation.

Fixes issue 498
Merge pull request #499 from jaredhoberock/issue-498

Use stream inside CUDA reduce implementation.
Add missing "using std::isinf"
Merge pull request #501 from dfontainenvidia/master

Missing using statement