Graphic EQ Effect

Thiss PR adds a 10 band static equalizer based on Biquad filters. The implementation of the Biquad filter is based on @daschuer's iireqs branch.
when where they removed? SetFilters() is used else where to just set new coefs without new, however a new sample rate is a case that makes the old filter unusable for fading. Can we find her a common solution for all EQs?

If sample rate changed, pause the filter = start from zero 
if Q or corners change, fade from the old filter.