add BH1750 sensor example

examples/osd/arduino-bh1750/BH1750FVI-master/BasicDemo/BasicDemo.ino

@@ -0,0 +1,23 @@
+#include <Wire.h>
+#include <BH1750FVI.h>
+
+BH1750FVI eye;
+word maxLux = 0;
+
+void setup() {
+  Wire.begin();
+  Serial.begin(115200);
+  //most basic setup with all default options
+  eye.begin();
+}
+
+void loop() {
+  //take a sensor reading, with units of Lux
+  word value = eye.getLightLevel();
+  byte spaces;
+  if(value>maxLux) maxLux=value;
+  spaces=map(value, 0, maxLux, 0, 32);
+  for(int i=0; i<spaces; i++) Serial.print(' ');
+  Serial.println(value);
+  delay(100);
+}