v0.3

What's new

• User guide
  
  Learning to use a crate with the documentation can be hard. There's now a guide to explain what can be done with Shipyard and how.

• No need to register components anymore
  
  Components had to be registered before accessing them by using World::new or World::register.
  Storages are now automatically created when they are first accessed.

• !Send and !Sync components
  
  All components had to be Send + Sync, this is a strict limitation to be sure storages can use the parallel feature.
  With 0.3 !Send and !Sync types can be stored and accessed while still following Rust's rules. These rules limit threading for these types but doesn't always prevent it.

• Unique components
  
  When we only need a single instance of a component, keeping an id around to access it can be annoying. A Unique component won't be attached to any entity but will have the storage all for itself.

• Components sorting

• No std support

• And more 😉