Adds protobuf definitions.

proto/mmelodies.proto

@@ -0,0 +1,33 @@
+syntax = "proto3";
+
+service ParameterService {
+	rpc SetParameters(ParameterRequest) returns (ParameterResponse) {};
+}
+
+message ParameterRequest {
+	optional uint32 velocity = 1;
+	optional uint32 tempo = 2;
+	optional uint32 delay_time = 3;
+	optional uint32 delay_feedback = 4;
+	optional uint32 filter_cutoff = 5;
+	optional uint32 echo_mix = 6;
+}
+
+message ParameterResponse {
+	uint32 velocity = 1;
+	uint32 tempo = 2;
+	uint32 delay_time = 3;
+	uint32 delay_feedback = 4;
+	uint32 filter_cutoff = 5;
+	uint32 echo_mix = 6;
+}
+
+service ScopeService {
+	rpc GetSamples(ScopeSamplesRequest) returns (ScopeSamplesResponse) {};
+}
+
+message ScopeSamplesRequest {}
+
+message ScopeSamplesResponse {
+	bytes samples = 1;
+}