new in 0.4
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 * trigger defaults to 0.6
 * pointer in logview better visible
 * update of logview when scale changed in menu
 * "text_width" replaced by "string_width"
 
new in 0.5
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 * sample frequency adjustable up to 48000 Hz (instead of 44000)
 * bugfix for newer OSS, which don't support small fragments
 * About-Box
 