Title : new
Usage : my $factory = new Bio::PhyloNetwork::TreeFactory();
Function: Creates a new Bio::PhyloNetwork::TreeFactory
Returns : Bio::PhyloNetwork::RandomFactory
Args : -numleaves => integer
-leaves => reference to an array (of leaves names)
Returns a Bio::PhyloNetwork::TreeFactory object. Such an object will
sequentially create binary phylogenetic trees
each time next_network is called.
If the parameter -leaves=>\@leaves is given, then the set of leaves of
these networks will be @leaves. If it is given the parameter
-numleaves=>$numleaves, then the set of leaves will be l1...l$numleaves.