added waveform selectors

src/synth/Envelope.cpp

@@ -7,6 +7,7 @@ Envelope::Envelope() {
 
 void Envelope::noteOn() {
     state_ = State::Attack;
+    // there's interntionally no envelope value_ reset here because slurs
 }
 
 void Envelope::noteOff() {
@@ -26,7 +27,7 @@ float Envelope::process() {
             state_ = State::Decay;
         }
         break;
-      case State::Decay: // TODO: if noteOff occurs during decay, release doesn't trigger until decay finishes
+      case State::Decay:
         value_ -= (1.0f - sustain_) / (decay_ * sampleRate_);
         if(value_ <= sustain_) {
             value_ = sustain_;