Fix all warnings

FossilOrigin-Name: 0e7605d101d4079a75f8b62b072f342cb5ce5ff95090cf2068318193de907e2c

src/Entity.h

@@ -1,5 +1,12 @@
-#import "PersistentEntity.h"
+#import <ObjFW/ObjFW.h>
 
-@interface Entity: PersistentEntity
-@property (nonatomic) bool spawned; // the only dynamic state of a map entity
+// map entity
+@interface Entity: OFObject
+@property (nonatomic) short x, y, z; // cube aligned position
+@property (nonatomic) short attr1;
+@property (nonatomic) unsigned char type; // type is one of the above
+@property (nonatomic) unsigned char attr2, attr3, attr4;
+@property (nonatomic) bool spawned;
+
++ (instancetype)entity;
 @end