Created plotter_tsereis.py, that makes tseries plot of quantiles. But there are lots of glitches now

• no straight way to embed plotnine plot into matplot lib. So exporting plotline plot as png, then using imread/imshow in matplot lib. it is not efficient, and also if it would ever look crisp in this method, particularly when there are legends for color, size etc.
• passing dict of arrays as data to be plotted, unlike 3-d array for tile plot, 4-d array for vprof plot. maybe that's OK...?
• plotter_multi doesnt expose layout arangement of Axes, For this trio plot, i may want to have two tile plot side by side, and tseries plot on top or bottom. Currently it is treated as same as tile plot, so it is very crowded.

It would make more sense to make this plotter_tseries to be triggered when plotter_multi is created, like, add_tseries argument, and code would add axes, use plotter_tsereis, with dict of arrays ceated on the fly, instead of user has to prepare them like it is now.