Move AlphaFilter out of EKF

EKF/estimator_interface.h

@@ -44,7 +44,7 @@
 #include <ecl.h>
 #include "common.h"
 #include "RingBuffer.h"
-#include "AlphaFilter.hpp"
+#include <AlphaFilter/AlphaFilter.hpp>
 #include "imu_down_sampler.hpp"
 #include "EKFGSF_yaw.h"
 #include "sensor_range_finder.hpp"

test/test_AlphaFilter.cpp

@@ -41,7 +41,7 @@
 #include <cmath>
 #include <matrix/math.hpp>
 
-#include "EKF/AlphaFilter.hpp"
+#include "AlphaFilter/AlphaFilter.hpp"
 
 using matrix::Vector3f;