TokenStream use VecDeque instead of Vec

[GreasySlug]

Currently the tokenStream uses Vec This method has self.lpop() and self.skip

    #[inline]
    fn skip(&mut self) {
        self.tokens.remove(0);
    }

    #[inline]
    fn lpop(&mut self) -> Token {
        self.tokens.remove(0)
    }

This self.remove(0) calculation cost is O(n) For short scripts, the computational cost is not a problem, but for scripts with more than 5k lines, the Parser starts to take a long time to process.

[mtshiba]

It would be more efficient to replace structures other than TokenStream that use Vec internally to perform remove(0) with VecDeque.