Add setting of Enclosure AmpMinimumLevel to the GUI

[jason-barba]

The Enclosure minimum amplitude level should be settable from the GUI. This is IMHO a parameter that is more related to the local hardware (like amplifier, speakers etc) and the environment of the VPO than to the sample set.

//Jens

[jason-barba]

Reference #769

[mutti-wilson]

I agree. This is something I adjust on sample sets to fit the room or just personal taste. Since it is only a volume adjustment and not changing EQ or other parameters, modifying it has no effect on the overall sound quality.

[mutti-wilson]

Check out this that could possibly change this all up.

#717