v0.3.0

Notable Changes

• Added getChildNodes to get a list of child nodes.
• Added addChildNodeAt, appendChild, insertNodeAfter, and insertNodeBefore to insert a new node.
• Added flatten to flatten parent-child nodes by performing full tree traversal using child-parent link.
• Added updateNode to update the data of a node.
• Added toString to serialize the current state of a node to a JSON string.

Other Changes

• Update dependencies: flattree@^0.8.1
• IE8 compatibility output