The bubble contribution keeps throwing me curve balls.  Between the
opacity of the code and it not doing what the comments say it does (or
what anyone other than Charles Robertson expects it to do), I am unable
to figure out how Mr. Robertson expected this code to behave.

My intention with version 4.0 was to slow the expansion of the bubbles
as they rise.  After I uploaded it Wednesday, I was eager to try it out
on my glasses of Champagne, but I got unexpected results.  Fiddling
around with the bubbles revealed that the expansion rate varies
depending on how high the beverage is above the Cartesian origin.  This
has implications for a long-stemmed wineglass.

So I wrote a test program to try out bubble containers of various
heights and sizes, and that's when things got really weird.  The columns
of bubbles would not stay in their lanes.

The issue is a section of code that "adjusts" the column positions, and
ultimately derives from parameters eFluidX, eFluidZ, and fRadius.
Common sense would suggest that this is an attempt to deal with a
non-vertical container, but that is not what this code section does.  In
fact, I cannot figure out what the heck Mr. Robertson is trying to do here.

Version 4.0.1 suppresses that adjustment, forcing the bubbles to stay
within their container.  Unfortunately, the Champagne flute must remain
upright for the bubble columns to be positioned in any quasi-realistic
manner.

As for the bubble expansion rate, I am not an expert on fluid dynamics,
and clearly neither is Mr. Robertson.  Version 4.0 adds a global
parameter to control the expansion rate of the bubbles.  Between that
parameter and varying the height of the bubble container, one should be
able to find a combination that resembles real life carbonation.

(Why did I skip from version 2.* to version 4?  Because the initial
version of this contribution was 3.6, so I wanted to leave 3.* clear.
I'm guessing that the 3.6 was a misunderstanding of the version field of
the Object Collection upload form.)

In the attached images, Bubble_Rate = 1.00 uses the original expansion
code, and Bubble_Rate = 0.45 is the new default expansion rate.  All
containers in these images are vertical, so a tilted orientation cannot
be the reason for the "adjustments."

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