- fix filter scene plot (plot 0db as actual 0db in the scene)
- DC is removed correctly from filtered signal
- generate std filter "User defined" with initial parameters only when not existing
- calculate mean function supports vector input data (more efficient)
- minimum for filter taps set to 9
- possible bug in filteroperator class fixed (cutting the non interesting part correctly now)
- minor change in the filter operator in order to use longer fft length
- add fft length label in filter window
- add group boxes to scaling window