todo_FigureErrorLoad

The behaviour of Optics.FigureErrorLoad is very rough. It was done to accept file error files with only 1 column. We should improve it to make it smart enough to handle different cases.

A typical input file can be like that (and can even have a header.... skipline functionality?)

0 -1.41E+00 0.05 -1.64E+00 0.1 -1.58E+00 0.15 -1.52E+00 0.2 -1.53E+00 0.25 -1.54E+00 0.3 -1.57E+00 0.35 -1.59E+00 0.4 -1.59E+00 0.45 -1.60E+00