Remove dr_libs submodule

.gitmodules

@@ -4,9 +4,6 @@
 [submodule "ext/nanosvg"]
 	path = ext/nanosvg
 	url = https://github.com/memononen/nanosvg.git
-[submodule "ext/dr_libs"]
-	path = ext/dr_libs
-	url = https://github.com/mackron/dr_libs.git
 [submodule "ext/osdialog"]
 	path = ext/osdialog
 	url = https://github.com/AndrewBelt/osdialog.git

ext/dr_libs

@@ -1 +0,0 @@
-Subproject commit 6fb1f8a9f8bb3198e05ee52aa38f177c499c1bef

src/dsp.cpp

@@ -1,10 +1,6 @@
 #include "dsp.hpp"
 
 
-#define DR_WAV_IMPLEMENTATION
-#include "../ext/dr_libs/dr_wav.h"
-
-
 namespace rack {