remove smithlab_cpp as a submodule
Squashed 'src/smithlab_cpp/' content from commit 9514219

git-subtree-dir: src/smithlab_cpp
git-subtree-split: 951421993646b22b46e3d2ac8f1a353c00b753a7
Merge commit '1f8d7d8f9c4e0ad847937e7fa2c942ba9c3aeb65' as 'src/smithlab_cpp'