Added simple oscillator example

modules/simple-osc/simple-osc.ino

@@ -0,0 +1,17 @@
+/*
+ * 
+ * Simple (PWM) Oscillator!
+ * 
+ */
+#define SPEAKER_PIN 11 
+
+void setup() {
+  // set pin 11 as output
+  pinMode(SPEAKER_PIN, OUTPUT);
+}
+
+void loop() {
+  // tone needs output pin and frequency. Here the frequency is determined by reading from analog input 2 (0-1023), or the top potentiometer
+  tone(SPEAKER_PIN, analogRead(A2)); 
+  delay(100); // a delay adds stability to the tone.
+}