This patch addresses a number of glitches discovered during interactive
testing and contains possible fixes (sub-patch test-ob-maxima fixes
batch testing on my system, but not interactive testing).

The test-ob-maxima patch may be due to a different Maxima version, but
I do not think so.  In batch testing test-ob-maxima passes contrary to
interactive mode.

The test-ob-python patch unsets org-src-preserve-indentation which I
have set.

The test-ob patch also unsets org-src-preserve-indentation.

The test-org-element patch indicates something weird on my system, I
want to report.  Should not be applied.

The test-org patch also unsets org-src-preserve-indentation.  This
reduces the number of failures to 2 while testing test-org
interactively.

Sorry to put them all together, but I do not know how to handle (ma)git
to keep the patches apart.

Regards -- Gerard