Add ``--simple`` to show only some key scores

[obo]

The current output is too detailed for common use. Add --simple which would select only:

• doclevel sacreBLEU for MT quality
• mwerSegmenter case-insensitive WER for ASR quality
• one of the delays (probably mwerSegmenter proportional?) for latency
• one of the flickers for stability

[mohammad2928]

It's done. For SLT evaluation, the following scores will be shown: 0- Signature
1- mwerSegmenter proportional without alignment 2- flicker size 3- docAsAWhole sacreBLEU An example of SLT output:

    Signature:  SLTev_4e179b8-elitrtestset_3ba5c8d
    tot      Delay         PnWn                   170767.130
    tot      Flicker       count_changed_content  9389
    tot      sacreBLEU     docAsAWhole            10.783

Also, for ASR evaluation, the following scores will be shown: 0- Signature
1- mwerSegmenter case-insensitive WER An example of ASR output:

    Signature:  SLTev_4e179b8-elitrtestset_3ba5c8d
    PnWn  0.272