The current dot file and svg graph included for the functional tests contains the full history of the gossip graph till reach the consensus.
We'd like ot investigate the most convenient way to trim down the graph, ideally only needs to contain the last few events before the consensus.
Note: this task also need to conver the work of:
update dump_graph/dot_parser or other stuff to support trim down graph
trim down the current included dot & svg file.