Refactor project

Crealned up some TODOs, FIXMEs etc. Added better error handling. Looks
better, feels better.

graphics/rse_graphics.h

@@ -3,9 +3,28 @@
 
 #include <stdint.h>
 
-void rse_graphics_init(void);
-uint8_t rse_graphics_run(void);
+#include "utilities/rse_commons.h"
 
+/**
+ * @brief Initializes graphics backend. This has to be called before any new mesh, texture or any other object is
+ * added
+ *
+ * @return rse_err_t RSE_ERROR_NO_ERROR on success
+ */
+rse_err_t rse_graphics_init(void);
+
+/**
+ * @brief Runs graphics engine. This has to be called after all objects are added to the scene
+ *
+ * @return rse_err_t RSE_ERROR_NO_ERROR on success
+ */
+rse_err_t rse_graphics_run(void);
+
+
+/**
+ * @brief Custom function for testing engine. Remove it whe releasing
+ *
+ */
 void rse_graphics_test_function(void);
 
 #endif /* RSE_GRAPHICS_H */