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.
Pausing and restarting a filter cases noise, because the filter buffers are still loaded with the samples from before the pause. I need a solution for this in the Bessel L/V as well. To avoid a criss cross merge we should add it in a separate PR. If you like I can do it.