Rescan if first scan fails in HIDMaster examples (#3089)

Sometimes the BT or BLE announcement doesn't show up during an initial
scan window.

Loop in the KeyboardPiano examples so that scans will be repeated until
something actually links up.

Fixes #3074

Author: earlephilhower

libraries/BluetoothHIDMaster/examples/KeyboardPiano/KeyboardPiano.ino

@@ -206,8 +206,10 @@ void setup() {
 
   hid.begin();
 
-  hid.connectAny();
-  // or hid.connectMouse();
+  do {
+    hid.connectAny();
+    // or hid.connectMouse();
+  } while (!hid.connected());
 }
 
 void loop() {

libraries/BluetoothHIDMaster/examples/KeyboardPianoBLE/KeyboardPianoBLE.ino

@@ -206,7 +206,9 @@ void setup() {
 
   hid.begin(true);
 
-  hid.connectBLE();
+  do {
+    hid.connectBLE();
+  } while (!hid.connected());
 }
 
 void loop() {