Missing Reflect impl for VecDeque

## What problem does this solve or what need does it fill?

It would be nice to be able to use a queue/stack like data structure in components; `VecDeque` fits that.

## What solution would you like?

Implement the reflect family of traits for VecDeque.

## What alternative(s) have you considered?

Using `Vec`, which is annoying to use as a queue.
