TODO

Fix needed:
- Correct matrix reshaping in freqResp() and other appropriate functions.

Improvements:
- The first direction is: add more functions to fanalyzer class. For example: plot magnitude from coefficients of SOS filter and etc.

- The second direction is to add appropriate C-implementations for digital filters, like FIR, IIR different forms and filter structure for SOS, what are will works with fsaver class.