Simpler HybridGaussianFoo constructors #3025

Job	Run time
ubuntu-clang-deprecated Debug	21m 19s
ubuntu-clang-deprecated Release	23m 21s
ubuntu-clang-quaternions Debug	22m 22s
ubuntu-clang-quaternions Release	23m 12s
ubuntu-clang-tbb Debug	23m 39s
ubuntu-clang-tbb Release	24m 37s
ubuntu-clang-cayleymap Debug	22m 23s
ubuntu-clang-cayleymap Release	23m 24s
ubuntu-clang-system-libs Debug	21m 37s
ubuntu-clang-system-libs Release	23m 0s
ubuntu-no-boost Debug	21m 35s
ubuntu-no-boost Release	23m 22s
ubuntu-no-unstable Debug	17m 42s
ubuntu-no-unstable Release	18m 26s
	5h 9m 59s

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