Cleanup compiler warnings #926

Job	Run time
CMake build on MacOS	5m 13s
CMake Serial Minimal Build on Linux	1m 10s
CMake Serial With Clawpack Build on Linux	9m 41s
CMake Serial With Clawpack and HDF Build on Linux	10m 47s
CMake Serial With GeoClaw Build on Linux	1m 15s
CMake Serial With CudaClaw (CUDA 10.1) Build on Linux	2m 55s
CMake Serial With CudaClaw (CUDA 11.3) Build on Linux	3m 25s
CMake MPI Minimal Build on Linux	2m 9s
CMake MPI With Clawpack Build on Linux	8m 31s
CMake MPI With Clawpack and HDF Build on Linux	9m 42s
CMake MPI With GeoClaw Build on Linux	2m 23s
CMake MPI With CudaClaw (CUDA 10.1) Build on Linux	2m 33s
CMake MPI With CudaClaw (CUDA 11.3) Build on Linux	4m 18s
CMake MPI With ThunderEgg Build on Linux	3m 54s
	1h 7m 56s

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