fix: remove unnecessary stuff

src/BandPassFilter.cpp

@@ -1,4 +1,4 @@
-#include "BandPassFilter.h"
+#include "Filter.h"
 #include "Settings.h"
 
 BandPassFilter::BandPassFilter() {

src/HighPassFilter.cpp

@@ -1,4 +1,4 @@
-#include "HighPassFilter.h"
+#include "Filter.h"
 #include "Settings.h"
 
 HighPassFilter::HighPassFilter() {

src/LowPassFilter.cpp

@@ -1,4 +1,4 @@
-#include "LowPassFilter.h"
+#include "Filter.h"
 #include "Settings.h"
 
 LowPassFilter::LowPassFilter() {

src/Synth.cpp

@@ -4,7 +4,6 @@
 #include "Logger.h"
 #include "OscillatorType.h"
 #include "Settings.h"
-#include "LowPassFilter.h"
 
 Synth::Synth(/* args */) {
     m_lfo = new LFO();