Add EQ to mixer

Requesting the addition of basic per-channel equalization controls (bass, mid, treble, or parametric EQ) to the built-in GP mixer plugin. There are apparently no third-party plugins that provide this within a single multi-channel mixer object. This feature would provide the ability to tweak individual instruments’ frequency response characteristics without using multiple EQ plugins, which consume “real estate” on the connections view and additional audio processing capacity.