Test for tree builders

Usage:

• include a header file with your builder class
• use your builder class in the main function

#include <getopt.h>

#include <boost/graph/graphviz.hpp>

#include "collectives/brsg_tree_builders.hpp"
using namespace MPIB::BRSG;

int main(int argc, char** argv) {
    int n = 8;
    int c;
    while ((c = getopt(argc, argv, "hn:")) != -1) {
        switch (c) {
            case 'h':
                cerr <<
"usage: trees [options]\n\
-h          help\n\
-n I            number of nodes in the tree\n";
                return 0;
                break;
            case 'n':
                n = atoi(optarg);
                break;
        }
    }
    Graph graph;
    Vertex r, u, v;
    Binomial_builder builder;
    builder.build(n, 0, 0, 0, graph, r, u, v);
    cout << "#Tree\n";
    write_graphviz(cout, graph);
    return 0;
}