Added a (registry object name -> registry object pointer) map to the save method so that registry reference by name can have their actor, sprite, spritesheet, and character references reset

include/akgl/sprite.h

@@ -24,7 +24,6 @@ typedef struct {
 
 typedef struct {
     uint8_t refcount;
-    akgl_SpriteSheet *sheet;
     uint8_t frameids[AKGL_SPRITE_MAX_FRAMES]; // which IDs on the spritesheet belong to our frames
     uint32_t frames; // how many frames are in this animation
     uint32_t width;
@@ -33,6 +32,7 @@ typedef struct {
     bool loop; // when this sprite is done playing, it should immediately start again
     bool loopReverse; // when this sprite is done playing, it should go in reverse order through its frames
     char name[AKGL_SPRITE_MAX_NAME_LENGTH];
+    akgl_SpriteSheet *sheet;
 } akgl_Sprite;
 
 // initializes a new sprite to use the given sheet and otherwise sets to zero