ArduCopter: use compass get_{field,offsets}() functions

Both functions are equivalent, so we're going to simply use
get_{field,offsets}() instead of get_{field,offsets}_milligauss().

ArduCopter/compassmot.cpp

@@ -124,7 +124,7 @@ uint8_t Copter::mavlink_compassmot(mavlink_channel_t chan)
     // store initial x,y,z compass values
     // initialise interference percentage
     for (uint8_t i=0; i<compass.get_count(); i++) {
-        compass_base[i] = compass.get_field_milligauss(i);
+        compass_base[i] = compass.get_field(i);
         interference_pct[i] = 0.0f;
     }
 
@@ -167,7 +167,7 @@ uint8_t Copter::mavlink_compassmot(mavlink_channel_t chan)
         // if throttle is near zero, update base x,y,z values
         if (throttle_pct <= 0.0f) {
             for (uint8_t i=0; i<compass.get_count(); i++) {
-                compass_base[i] = compass_base[i] * 0.99f + compass.get_field_milligauss(i) * 0.01f;
+                compass_base[i] = compass_base[i] * 0.99f + compass.get_field(i) * 0.01f;
             }
 
             // causing printing to happen as soon as throttle is lifted
@@ -175,7 +175,7 @@ uint8_t Copter::mavlink_compassmot(mavlink_channel_t chan)
 
             // calculate diff from compass base and scale with throttle
             for (uint8_t i=0; i<compass.get_count(); i++) {
-                motor_impact[i] = compass.get_field_milligauss(i) - compass_base[i];
+                motor_impact[i] = compass.get_field(i) - compass_base[i];
             }
 
             // throttle based compensation

ArduCopter/motors.cpp

@@ -358,7 +358,7 @@ bool Copter::pre_arm_checks(bool display_failure)
         }
 
         // check for unreasonable compass offsets
-        Vector3f offsets = compass.get_offsets_milligauss();
+        Vector3f offsets = compass.get_offsets();
         if(offsets.length() > COMPASS_OFFSETS_MAX) {
             if (display_failure) {
                 gcs_send_text_P(MAV_SEVERITY_CRITICAL,PSTR("PreArm: Compass offsets too high"));
@@ -367,7 +367,7 @@ bool Copter::pre_arm_checks(bool display_failure)
         }
 
         // check for unreasonable mag field length
-        float mag_field = compass.get_field_milligauss().length();
+        float mag_field = compass.get_field().length();
         if (mag_field > COMPASS_MAGFIELD_EXPECTED*1.65f || mag_field < COMPASS_MAGFIELD_EXPECTED*0.35f) {
             if (display_failure) {
                 gcs_send_text_P(MAV_SEVERITY_CRITICAL,PSTR("PreArm: Check mag field"));

ArduCopter/setup.cpp

@@ -450,7 +450,7 @@ void Copter::report_compass()
     // mag offsets
     Vector3f offsets;
     for (uint8_t i=0; i<compass.get_count(); i++) {
-        offsets = compass.get_offsets_milligauss(i);
+        offsets = compass.get_offsets(i);
         // mag offsets
         cliSerial->printf_P(PSTR("Mag%d off: %4.4f, %4.4f, %4.4f\n"),
                         (int)i,

ArduCopter/test.cpp

@@ -116,8 +116,8 @@ int8_t Copter::test_compass(uint8_t argc, const Menu::arg *argv)
             counter++;
             if (counter>20) {
                 if (compass.healthy()) {
-                    const Vector3f &mag_ofs = compass.get_offsets_milligauss();
-                    const Vector3f &mag = compass.get_field_milligauss();
+                    const Vector3f &mag_ofs = compass.get_offsets();
+                    const Vector3f &mag = compass.get_field();
                     cliSerial->printf_P(PSTR("Heading: %ld, XYZ: %.0f, %.0f, %.0f,\tXYZoff: %6.2f, %6.2f, %6.2f\n"),
                                         (wrap_360_cd(ToDeg(heading) * 100)) /100,
                                         (double)mag.x,