Make bindings resilient to OOM errors

[tomaka]

This PR proposes a relatively simple but maybe controversial change.

In the functions that return a Vec, instead of using Vec::with_capacity and similar, we use Vec::new() followed with Vec::try_reserve. If try_reserve fails, we return VK_ERROR_OUT_OF_HOST_MEMORY.

Note that there's no shorter way on stable Rust to do this. Notably, try_with_capacity is unstable.

If I'm not mistaken, the bindings now never panic in case of OOM.

I personally don't have a need for this change, but I thought that this was a neat thing to add.

[Ralith]

Not sure how useful this is in practice, but it seems like a strict improvement, and not too bad to maintain.