Read perseus network collection folder format
    
    >>> network_table, networks = read_networks(folder)
    
    :param folder: Path to network collection
    :returns: Network table and dictionary with 'name', 'edge_table', and 'node_table' keys.

def read_networks(folder):
    """
    Read perseus network collection folder format
    
    >>> network_table, networks = read_networks(folder)
    
    :param folder: Path to network collection
    :returns: Network table and dictionary with 'name', 'edge_table', and 'node_table' keys.
    """
    network_table = read_perseus(path.join(folder, "networks.txt"))
    networks = {}
    for name, guid in network_table[['Name', 'GUID']].values:
        networks[guid] = {
                'name': name,
                'guid': guid,
                'node_table': read_perseus(path.join(folder, "{}_nodes.txt".format(guid))),
                'edge_table': read_perseus(path.join(folder, "{}_edges.txt".format(guid)))
                }
    return network_table, networks