Fix public header includes

Applications, and thus our public headers, should be included as
`#include <libvmaf/libvmaf.h>`. Adding `include/libvmaf` into include
directories means applications could do e.g. `#include <feature.h>`
which is ambiguous.

Author: xclaesse

libvmaf/include/libvmaf/libvmaf.h

@@ -22,9 +22,9 @@
 #include <stdint.h>
 #include <stdio.h>
 
-#include "libvmaf/model.h"
-#include "libvmaf/picture.h"
-#include "libvmaf/feature.h"
+#include <libvmaf/model.h>
+#include <libvmaf/picture.h>
+#include <libvmaf/feature.h>
 
 #ifdef __cplusplus
 extern "C" {

libvmaf/include/libvmaf/libvmaf_cuda.h

@@ -19,7 +19,7 @@
 #ifndef __VMAF_CUDA_H__
 #define __VMAF_CUDA_H__
 
-#include "libvmaf/libvmaf.h"
+#include <libvmaf/libvmaf.h>
 
 #ifdef __cplusplus
 extern "C" {

libvmaf/include/libvmaf/model.h

@@ -21,7 +21,7 @@
 
 #include <stdint.h>
 
-#include "feature.h"
+#include <libvmaf/feature.h>
 
 #ifdef __cplusplus
 extern "C" {

libvmaf/src/meson.build

@@ -572,5 +572,4 @@ pkg_mod.generate(libraries: libvmaf,
     name: 'libvmaf',
     filebase: 'libvmaf',
     description: 'VMAF, Video Multimethod Assessment Fusion',
-    subdirs: [ '.', 'libvmaf']
 )