Squashed 'src/smithlab_cpp/' content from commit 9514219

git-subtree-dir: src/smithlab_cpp
git-subtree-split: 951421993646b22b46e3d2ac8f1a353c00b753a7
Merge commit '815557383fe249badce4a4f84c8d57473ce08b9e' as 'src/smithlab_cpp'