Squashed 'libot/' changes from 9464916..cf85c0e

cf85c0e Add UTF8 support
9d78fb3 Add CONTRIBUTING.md
4259681 Change ot_size so delete subtracts from the size
b608f3a Add LICENSE

git-subtree-dir: libot
git-subtree-split: cf85c0ef6f13cd47ad8a463bf8ff06f46cdf1b70
Merge commit '595b5f4113114f0fafcc0a2a890654c075b429cb'
Upgrade to libot v0.2.0