Remove models library submodule in order to make it a subtree.
Squashed 'public/modelslib/' content from commit d49b327

git-subtree-dir: public/modelslib
git-subtree-split: d49b32744d7470e233d4f1f6a23f2cb70cd29c21
Merge commit '0ccab22250115ba3c12cc5548239b1550336b873' as 'public/modelslib'