Added static class that generates OnlineIirFilter objects from Butterworth filter. Butterworth filters were only generating coefficients, while now it is possible to directly obtain an OnlineIirFilter object designed using the Butterworth filter designer.
Added tests to check that the online filters produce the expected output.
Fixed issue in Butterworth.IirCoefficients.Notch() where wc2 frequency was not pre-warped and wc1 was pre-warped twice.
Removed unneeded System.Linq inclusion in MathFunctions.cs
Added static class that generates OnlineIirFilter objects from Butterworth filter. Butterworth filters were only generating coefficients, while now it is possible to directly obtain an OnlineIirFilter object designed using the Butterworth filter designer.
Added tests to check that the online filters produce the expected output.
Fixed issue in Butterworth.IirCoefficients.Notch() where wc2 frequency was not pre-warped and wc1 was pre-warped twice.
Removed unneeded System.Linq inclusion in MathFunctions.cs