Copter: added DEV_OPTIONS parameter

this is for little used options to allow standard firmware builds to
enable those options for development purposes

First option is for MAVLink based ADSB avoidance

ArduCopter/GCS_Mavlink.cpp

@@ -960,7 +960,10 @@ void GCS_MAVLINK_Copter::handle_change_alt_request(AP_Mission::Mission_Command &
 void GCS_MAVLINK_Copter::packetReceived(const mavlink_status_t &status,
                                         mavlink_message_t &msg)
 {
-    copter.avoidance_adsb.handle_msg(msg);
+    if (copter.g2.dev_options.get() & DevOptionADSBMAVLink) {
+        // optional handling of GLOBAL_POSITION_INT as a MAVLink based avoidance source
+        copter.avoidance_adsb.handle_msg(msg);
+    }
     GCS_MAVLINK::packetReceived(status, msg);
 }
 

ArduCopter/Parameters.cpp

@@ -1000,6 +1000,13 @@ const AP_Param::GroupInfo ParametersG2::var_info[] = {
     // @Path: ../libraries/AP_AdvancedFailsafe/AP_AdvancedFailsafe.cpp
     AP_SUBGROUPINFO(afs, "AFS_", 6, ParametersG2, AP_AdvancedFailsafe),
 #endif
+
+    // @Param: DEV_OPTIONS
+    // @DisplayName: Development options
+    // @Description: Bitmask of developer options. The meanings of the bit fields in this parameter may vary at any time. Developers should check the source code for current meaning
+    // @Bitmask: 0:ADSBMavlinkProcessing
+    // @User: Advanced
+    AP_GROUPINFO("DEV_OPTIONS", 7, ParametersG2, dev_options, 0),
     
     AP_GROUPEND
 };

ArduCopter/Parameters.h

@@ -562,6 +562,9 @@ public:
     // advanced failsafe library
     AP_AdvancedFailsafe_Copter afs;
 #endif
+
+    // developer options
+    AP_Int32 dev_options;
 };
 
 extern const AP_Param::Info        var_info[];

ArduCopter/defines.h

@@ -276,6 +276,11 @@ enum LandStateType {
     LandStateType_Descending = 1
 };
 
+// bit options for DEV_OPTIONS parameter
+enum DevOptions {
+    DevOptionADSBMAVLink = 1,
+};
+
 //  Logging parameters
 #define TYPE_AIRSTART_MSG               0x00
 #define TYPE_GROUNDSTART_MSG            0x01