AP_Beacon: Added Marvelmind beacon example.

This commit includes an example program to
run the code of AP_Marvelmind class.
It also includes a dump from the marvelmind
serial as well as a script that injects
this dump into the example for demonstration.

libraries/AP_Beacon/examples/AP_Marvelmind_test/AP_Marvelmind_test.cpp

@@ -0,0 +1,54 @@
+/*
+  simple test of UART interfaces
+ */
+
+#include <AP_HAL/AP_HAL.h>
+#include <AP_Beacon/AP_Beacon_Marvelmind.h>
+#include <AP_Beacon/AP_Beacon.h>
+#if HAL_OS_POSIX_IO
+#include <stdio.h>
+#endif
+
+void setup();
+void loop();
+
+const AP_HAL::HAL& hal = AP_HAL::get_HAL();
+static AP_SerialManager serial_manager;
+AP_Beacon beacon{serial_manager};
+
+// try to set the object value but provide diagnostic if it failed
+void set_object_value(const void *object_pointer,
+                      const struct AP_Param::GroupInfo *group_info,
+                      const char *name, float value)
+{
+    if (!AP_Param::set_object_value(object_pointer, group_info, name, value)) {
+        printf("WARNING: AP_Param::set object value \"%s::%s\" Failed.\n",
+                            group_info->name, name);
+    }
+}
+
+void setup(void)
+{
+    set_object_value(&beacon, beacon.var_info, "_TYPE", 2.0f);
+    set_object_value(&serial_manager, serial_manager.var_info, "0_PROTOCOL", 13.0f);
+    serial_manager.init();
+    beacon.init();
+}
+
+void loop(void)
+{
+    static int count = 0;
+    beacon.update();
+    Vector3f pos;
+    float accuracy = 0.0f;
+    beacon.get_vehicle_position_ned(pos, accuracy);
+    if (pos.x > 0.001f) {
+        printf("%f %f %f\n", pos.x, pos.y, pos.z);
+        count++;
+    }
+    hal.scheduler->delay(1000);
+    if (count == 3)
+        exit(0);
+}
+
+AP_HAL_MAIN();

libraries/AP_Beacon/examples/AP_Marvelmind_test/inject_marvelmind_dump.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+
+./waf configure --board=linux --debug
+./waf build --target=examples/AP_Marvelmind_test -j6
+repo_root="$(git rev-parse --show-toplevel)/"
+"$repo_root/build/linux-debug/examples/AP_Marvelmind_test" -A tcp:127.0.0.1:5111 &
+sleep 1
+cat ${repo_root}/libraries/AP_Beacon/examples/AP_Marvelmind_test/sample.dump| socat - tcp:127.0.0.1:5111
+wait

libraries/AP_Beacon/examples/AP_Marvelmind_test/wscript

@@ -0,0 +1,7 @@
+#!/usr/bin/env python
+# encoding: utf-8
+
+def build(bld):
+    bld.ap_example(
+        use='ap',
+    )