void beforeRemoved(OrderedReadyNodes readyNodes) {
        --numNodesBeforeThis;

        if (ready()) {
            readyNodes.add(this);
        }
    }
A node in a dependency graph.

Dependencies must declared as follows:
    a.before(b) , where a,b are nodes.

The following dependencies are currently allowed:
    searcher.before(name)
    name.before(searcher)
    searcher1.before(searcher2)

 Where name designates a NameProvider( either a phase or a set of searchers).

@author Tony Vaagenes
container-core/src/main/java/com/yahoo/component/chain/dependencies/ordering/Node.java