Minor refactoring of MIKMIDIEndpointSynthesizer instrument selection code.
Minor refactoring of MIKMIDIEndpointSynthesizer instrument selection code.

alessandrostone/MIKMIDI,bamboostick/MIKMIDI,alessandrostone/MIKMIDI,bamboostick/MIKMIDI,bamboostick/MIKMIDI,alessandrostone/MIKMIDI