Update build files with latest gallery tag.
Add io in src.
IO build.
Update version in package.json.
Adding history updates
Update io HISTORY.
Merge tag 'v3.10.3' into live-docs
Fix typos in App GitHub contributors example
Remove dupe keys from series collection config example
Remove dupe keys from chart-objectstyles partial file.
Tree.Openable: Add missing API doc params.

Fixes #869
Build tree-openable. Doc changes only.