lisa.stats: Use holoviews for plots
lisa.stats: Use holoviews for plots

BREAKING CHANGE

Plot methods of lisa.stats.Stats used to return matplotlib Axes objects,
they now return holoviews elements.

ARM-software/lisa,ARM-software/lisa,ARM-software/lisa,credp/lisa,credp/lisa,credp/lisa,credp/lisa,ARM-software/lisa