Squashed 'native/libot/' changes from 4259681..cf85c0e

cf85c0e Add UTF8 support
9d78fb3 Add CONTRIBUTING.md

git-subtree-dir: native/libot
git-subtree-split: cf85c0ef6f13cd47ad8a463bf8ff06f46cdf1b70
Merge commit '6706dfdb1dd439b83448c3399d95b13e40a6036b'
Release for v0.1.4