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 

  
IMHO it make sense to be here, because it is the Nature of a manager to know such things.
This way we do not need to care about the internal structure of back ends and external effects in future in the EQ preference pain.