AP_RangeFinder: added an example program

libraries/AP_RangeFinder/examples/RFIND_test/Makefile

@@ -0,0 +1 @@
+include ../../../../mk/apm.mk

libraries/AP_RangeFinder/examples/RFIND_test/RFIND_test.pde

@@ -0,0 +1,59 @@
+/*
+ *  RangeFinder test code
+ */
+ 
+#include <AP_RangeFinder.h>
+#include <AP_Common.h>
+#include <AP_HAL.h>
+#include <Filter.h>
+#include <AP_Progmem.h>
+#include <AP_Math.h>
+#include <AP_Param.h>
+#include <GCS_MAVLink.h>
+#include <AP_HAL_Empty.h>
+#include <AP_HAL_AVR.h>
+#include <AP_HAL_AVR_SITL.h>
+#include <AP_HAL_PX4.h>
+#include <AP_HAL_Linux.h>
+#include <DataFlash.h>
+#include <AP_GPS.h>
+#include <AP_InertialSensor.h>
+#include <AP_ADC.h>
+#include <AP_Baro.h>
+#include <AP_AHRS.h>
+#include <AP_Compass.h>
+#include <AP_Declination.h>
+#include <AP_Airspeed.h>
+#include <AP_Vehicle.h>
+#include <AP_NavEKF.h>
+#include <AP_ADC_AnalogSource.h>
+#include <AP_Notify.h>
+#include <AP_Mission.h>
+#include <AP_Scheduler.h>
+
+const AP_HAL::HAL& hal = AP_HAL_BOARD_DRIVER;
+
+static RangeFinder sonar;
+
+void setup()
+{
+    // print welcome message
+    hal.console->println("Range Finder library test");
+
+    // setup for auto-detect with analog pin 13
+    AP_Param::set_object_value(&sonar, sonar.var_info, "_TYPE", RangeFinder::RangeFinder_TYPE_AUTO);
+    AP_Param::set_object_value(&sonar, sonar.var_info, "_PIN", 13);
+
+    // initialise sensor, delaying to make debug easier
+    hal.scheduler->delay(2000);
+    sonar.init();
+}
+
+void loop()
+{
+    // Delay between reads
+    hal.scheduler->delay(100);
+    
+    hal.console->printf("Distance %.2f\n", (float)sonar.distance_cm());
+}
+AP_HAL_MAIN();