deeptools/HiCExplorer: Mid-Winter release 2020 bug fix 3

Fixing the wrong p-value computation in for chicViewpoint. New method is more accurate for floating points. Fixing a bug in chicViewpointBackgroundModel and chicQualityControl if an non-existing reference point was used. Improving all chic* modules with a capturing of errors in sub-processes. It is now guaranteed that the computation will terminate. Either successfull or by error. Add option 'truncateZero' to chicViewpointBackgroundModel: This removes all zero values for the distributions before fitting to fight over dispersion. Add option 'decimalPlaces' to chicViewpoint to adjust the decimal places in the output for all floating values. Helpful for really small p-values Add option 'truncateZeroPvalues' to chicSignificantInteractions to set all p-values which are 0 to 1 and are therefore ignored. Add option 'truncateZeroPvalues' to chicPlotViewpoint to set all p-values which are 0 to 1 and do not disturb the presentation of real p-value