lisa.stats: Add Stats.plot_stats(kind='horizontal_bar') option
lisa.stats: Add Stats.plot_stats(kind='horizontal_bar') option

Allow different kind of plots:

    * horizontal_bar (new default)
    * vertical_bar (old default)

The new default has been chosen since it increases a lot the readability
of bar labels (avoiding vertical text) and also fixes bar tip annotation
overlap issue.

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