10.06.19 : 0.6 : first distributed version
17.06.19 : 0.7 : corrected terminology in filter options: now LOWF is really the 
           lower edge filter frequency and HIGHF is really the upper edge. Hence,
           setting only HIGHF applies a low pass filter!
24.06.19 : 1.0 : added option NOISEPROFILE
30.06.19 : 1.1 : bug fix : conversion of MP3 files failed -> fixed
07.07.19 : 1.2 : eliminated sox warnings with NOISE > 0
11.05.21 : 1.3 : set Kaiser filter tabs number to 20000 to get sharper filter edges
06.12.21 : 2.0 : added N-HANS filtering (options 'NHANS', 'pos', 'neg')
12.01.22 : 2.1 : suppress stderr output of sox 
