Reorganize files and add Mandelbrot shader

src/renderer.h

@@ -0,0 +1,12 @@
+#ifndef RENDERER_H
+#define RENDERER_H
+
+#include <GLFW/glfw3.h>
+
+GLFWwindow *initialize_window(int width, int height);
+unsigned int initialize_vertices();
+void process_input(GLFWwindow *window, unsigned int *shader_program,
+                   const char *const fragment_shader_file);
+void framebuffer_size_callback(GLFWwindow *window, int width, int height);
+
+#endif /* RENDERER_H */