mie: ctx is now used to query the type of a value

this allows value get_type callbacks to use mie_ctx to obtain mie_type pointers,
rather than having to define their own static versions of the type structs.

mie/value.c

@@ -46,10 +46,10 @@ void mie_value_destroy(struct mie_value *val)
 	free(val);
 }
 
-struct mie_type *mie_value_get_type(struct mie_value *val)
+struct mie_type *mie_value_get_type(struct mie_value *val, struct mie_ctx *ctx)
 {
 	if (val->v_type->t_get_type) {
-		return val->v_type->t_get_type(val);
+		return val->v_type->t_get_type(val, ctx);
 	}
 
 	return NULL;