now the frame is not the one from the entire Axes, but just of the
bbox like in matplotlib.

I add two keywords, forceRatioOnHeight/Width these key words
ignores the Height/Width respectively and compute them
from the Width/Height and the ratio.

Since the ratio is not needed anymore it may be intersting to put it
as a optional keyword.

I am also thinking of one keywords:
FitEntireAxesInFrame, which would fit the entire pictures
(with axis labels, and ticks label, as well as centered in the frame)