Fix and enhance bag plots.

Fix the way how the bags are computed. They are now performed at
50 and 99% of the distribution.
Functional bag plots also create a median serie which is the
median line of all input series. Outliers series are also
tagged with an "_outlier" extension in their name.

Change-Id: I990428c9b79278be9be725491232b3e9d69190b0
Merge topic 'FixAndEnhanceBagPlots' into master

df6c71a9 Fix and enhance bag plots.