switch to setup for Arduino Boards Manager

digistump-avr/libraries/DigisparkCDC/examples/Echo/Echo.ino

@@ -0,0 +1,21 @@
+#include <DigiCDC.h>
+void setup() {                
+  // initialize the digital pin as an output.
+  SerialUSB.begin(); 
+}
+
+// the loop routine runs over and over again forever:
+void loop() {
+  
+  if (SerialUSB.available()) {
+    SerialUSB.write(SerialUSB.read());
+  }
+  
+   //SerialUSB.delay(10);
+   /*
+   if you don't call a SerialUSB function (write, print, read, available, etc) 
+   every 10ms or less then you must throw in some SerialUSB.refresh(); 
+   for the USB to keep alive - also replace your delays - ie. delay(100); 
+   with SerialUSB.delays ie. SerialUSB.delay(100);
+   */
+}