Extension for Tree that adds the concept of open/closed state for nodes.
Tree.OpenablecloseNodenode
                    
                [options]
                    
                Closes the specified node if it isn't already closed.
node
                        Tree.Node
                    
                    
                    Node to close.
[options]
                        Object
                        optional
                    
                    
                    Options.
[silent=false]
                                    Boolean
                                    optional
                                
                                If true, the close event
        will be suppressed.
[src]
                                    String
                                    optional
                                
                                Source of the change, to be passed along to the event facade of the resulting event. This can be used to distinguish between changes triggered by a user and changes triggered programmatically, for example.
openNodenode
                    
                [options]
                    
                Opens the specified node if it isn't already open.
node
                        Tree.Node
                    
                    
                    Node to open.
[options]
                        Object
                        optional
                    
                    
                    Options.
[silent=false]
                                    Boolean
                                    optional
                                
                                If true, the open event
        will be suppressed.
[src]
                                    String
                                    optional
                                
                                Source of the change, to be passed along to the event facade of the resulting event. This can be used to distinguish between changes triggered by a user and changes triggered programmatically, for example.