equalizer section

This is a work in progress branch for the EQ preferences. 
Any comment is welcome.
Many controllers have a knob labelled "filter" -- the VCI-400 for instance.  It's a rotary knob whose default position in the center and is often positioned directly above the channel's fader.  On a Pioneer mixer this is the "colour" knob.  Should we have some more description of what knob to look for on a controller?