remove /include/twn_config.h, move defauls to relevant headers

src/twn_textures_c.h

@@ -11,6 +11,11 @@
 #include <stdbool.h>
 
 
+#define TEXTURE_ATLAS_SIZE_DEFAULT 2048
+#define TEXTURE_ATLAS_BIT_DEPTH 32
+#define TEXTURE_ATLAS_FORMAT SDL_PIXELFORMAT_RGBA32
+
+
 typedef struct Texture {
     Rect srcrect;            /* position in atlas */
     SDL_Surface *data;          /* original image data */