Consider implementing more ops for `Ref<T>`

[chronicl]

By implementing

impl<T1, T2> Add<T1> for Ref<T2>
where T2: Add<T1>

// and
impl<T> Add<Ref<T>> for  vec<N, L>
where vec<N, L>: Add<T>

// and similarly for sm::Struct<S>, u32, i32, f32 and so on

for all binary operations, we can massively improve the ergonomics of using Ref.
Would you be open for that?
I implemented it already so I could prepare a PR very quickly.

Also, there is a lot of functions/methods in shame that accept impl To<T> and it would be nice if those accepted Ref<T>. For testing purposes I implemented ToGpuType for Ref<T> which implies impl To<T> for Ref<T> and it works great, but of course that's not the intended way for ToGpuType to be used.

With those two improvements I think Buffer could safely be removed in favor of renaming BufferRef to Buffer.