CMake

Some cleanup and improvements, added benchmarks. #115

Job	Run time
build (ubuntu-latest)	1m 26s
Format Check	17s
build (macos-latest)	1m 8s
build (windows-latest)	2m 58s
benchmark (ubuntu-latest)	8s
test (ubuntu-latest)	11s
benchmark (macos-latest)	9s
test (windows-latest)	34s
benchmark (windows-latest)	28s
test (macos-latest)	12s
cleanup_cache (windows-latest)	39s
cleanup_cache (ubuntu-latest)	5s
cleanup_cache (macos-latest)	4s
	8m 19s

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