Quasars/orange-spectroscopy: Release 0.4.2

[ENH] Tests for irfft calcuations (agilent data) [ENH] Rock XAS readers [ENH] OWPreprocess: show up to 100 preview spectra [ENH] Increase shown spectra limit from 100 to 1000 [ENH] Normalize by reference [ENH] Show preprocessor exceptions as errors in Preprocess Spectra [ENH] Preprocessor warnings [ENH] Enable changing the reference frame in Stack Align [FIX] owpreprocess: fix segfault on widget removal [FIX] Interferogram to Spectrum: fix zero-filling factor [FIX] Subtract DC value from IFG [FIX] Fix rubberband (qhull) ValueError on all-NaN sample row [FIX] OWIntegrate: fix non-meta output Test and handle (-) infs in preprocessor