add vector fonts support

src/coders/vector_fonts.hpp

@@ -1,5 +1,20 @@
 #pragma once
 
+#include <memory>
+#include <string>
+
+class Font;
+
 namespace vector_fonts {
+    class FontFile {
+    public:
+        virtual ~FontFile() {}
+    
+        virtual std::unique_ptr<Font> createInstance(int size) = 0;
+    };
+
     void initialize();
+    void finalize();
+
+    std::unique_ptr<vector_fonts::FontFile> load_font(const std::string& filename);
 }