Acro fix - we had lost the scaling of Acro mode in 2.1. This restores that.

ArduCopter/ArduCopter.pde

@@ -1415,8 +1415,8 @@ void update_roll_pitch_mode(void)
 	switch(roll_pitch_mode){
 		case ROLL_PITCH_ACRO:
 			// ACRO does not get SIMPLE mode ability
-			g.rc_1.servo_out = get_rate_roll(g.rc_1.control_in);
-			g.rc_2.servo_out = get_rate_pitch(g.rc_2.control_in);
+			g.rc_1.servo_out = get_acro_roll(g.rc_1.control_in);
+			g.rc_2.servo_out = get_acro_pitch(g.rc_2.control_in);
 			break;
 
 		case ROLL_PITCH_STABLE:

ArduCopter/Attitude.pde

@@ -80,6 +80,22 @@ get_stabilize_yaw(int32_t target_angle)
 #endif
 }
 
+static int
+get_acro_roll(int32_t target_rate)
+{
+	target_rate = target_rate * g.pi_stabilize_roll.kP();
+	target_rate = constrain(target_rate, -10000, 10000);
+	return get_rate_roll(target_rate);
+}
+
+static int
+get_acro_pitch(int32_t target_rate)
+{
+	target_rate = target_rate * g.pi_stabilize_pitch.kP();
+	target_rate = constrain(target_rate, -10000, 10000);
+	return get_rate_pitch(target_rate);
+}
+
 static int
 get_rate_roll(int32_t target_rate)
 {