CLI routines still use v0.2 API in v0.3rc1

[ptooley]

Issue with 0.3 cli routines:

[orudyy@fju749 serial] pypop-hybrid-metrics mhdg-parallel-3d.div1.1Nodes.1x1.prv
Traceback (most recent call last):                                                                                                                             
  File "/home/orudyy/.local/bin/pypop-hybrid-metrics", line 11, in <module>
    load_entry_point('pypop==0.3rc1+g121db96', 'console_scripts', 'pypop-hybrid-metrics')()
  File "/home/orudyy/.local/lib/python3.7/site-packages/pypop/cli.py", line 279, in hybrid_cli_metrics
    metric_table.savefig(config.metric_table)
AttributeError: 'MetricTable' object has no attribute 'savefig'