Bump to pom-scijava 1.89

Signed-off-by: Jenkins <jenkins@dev.loci.wisc.edu>
Bump to pom-scijava 1.90

Signed-off-by: Jenkins <jenkins@dev.loci.wisc.edu>
Bump to pom-scijava 1.91

Signed-off-by: Jenkins <jenkins@dev.loci.wisc.edu>
Bump to pom-scijava 1.92

Signed-off-by: Jenkins <jenkins@dev.loci.wisc.edu>
AbstractCalibratedSpace: fix recursion bug

The default CalibratedSpace#averageScale(int) implementation was
*supposed* to call axis(int).averageScale(0, 1), since in the case of
CalibratedSpaces which may not be Intervals, we do not know of any
better bounds to use.

Somehow, I mangled it and the problem was not caught until now. So this
change also adds a unit test to ensure the problem does not recur.
Eliminate warnings
realSymmetricMatrix2x2 now handles negative scales

This is part of the fix of issue #33.
Merge branch 'master' into knip