This reverts commit 94511568.

Change the calculation of the spectra ids limits from SANSDiagnosis that
used to return a wrong range due to a false assumption. This patch solves
the issue, but advise is given in order to improve the performance. re #2470

Required for IPython

The U matrix was being multiplied in twice since ConvertToMD now does
this, as it should.

This necessitated an amendment of a make file to ensure scoped file is available to the test.

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>

And doesn't test what it was originally written for anyway.

Also improve readability of tests.

Changed axis to report in Time unit. Inputs are converted from relative time to absolute time in nanoseconds for the calculation. The xaxis is provided in relative time.