* add tool to analyze log

* minor fix

* plot multi keys, use subparser, modify code

* add two method add_plot_parser and add_time_parser, minor fix

* minor fix

* move add parser func outside main

* move subparser.add inside add parser func

* rewrite multigpu testing with mmddp

* fix an indent

* update slurm testing script

* update readme and scripts

* support GN in RetinaHead

* add conv_cfg argument for RetinaHead

* add model upgrading tool and update retinanet model urls

* minor fix for regex strings

* implement _init_dist_slurm()

* add slurm train/test scripts

* fix linting error

* minor fix