Method unkill

chapter20/src/main/java/com/seaofnodes/simple/node/Node.java:280–283

()

    // Test "keep" status
    public boolean iskeep() { return _outputs.find(null) != -1; }
    public void unkill() {
        if( unkeep().isUnused() )
            kill();
    }


    // Replace self with nnn in the graph, making 'this' go dead