BedMetrics: support dataset *.yaml as failed tracks

[iromeo]

At the moment we use *.csv format which isn't related to our internal formats, like *.yaml datasets, etc, so it gives user freedom to use it outside our project scope. In 'epigenome' project FailedTracksTableReport tools allows to generate proper *.csv table for given *.yaml dataset. It will be more convenient for our project to support *.yaml file directly in order to remove duplicated failed tracks annotations + not to update *.csv after *.yaml file has been changed. I suggest to support both *.yaml and *.csv tables here.