Eq rack2

This is an updated version on Nicus EQ Rack Branch.
It enables the full power of the effect back-end for the EQ Knobs as well.

You can select which EQ should work on which deck and you can load any other effect to the EQ Slots.

Next steps to merge:
* Add a second Effect slot, to utilize the Filter knob / fourth band, some Controllers offer.
* Add an effect chain to preferences for master EQ 

  
Ah yes that is probably a regression.  I wonder if this will be ever noticed. With this model, he can add an EQ as well to all other devices. We have just to register them.  

I think it will be best do do it in the way of the master EQ later. Is it Ok for you? 
This would be a static EQ nature, not suitable for mixing because the missing GUI knobs.
Valid for mic and aux.  

We could also expose the group enable buttons in the preference GUI to Map the hardware Knobs to sampler as well. L/R Bus could be a valid use case  ...