remove_until like API, removes all items until a predicate matches

[Dav1dde]

The idea is similar to #47 but instead of being able to skip items, it would remove all items until a predicate matches (excluding that element).

For example in Rust pseudo code:

let mut queue = PriorityQueue::new();
queue.push(1, "a");
queue.push(2, "b");
queue.push(3, "c");

let items = queue.remove_until(|k| k < 3).collect::<Vec<_>>();
assert_eq!(items, vec![(1, "a"), (2, "b")]);

assert_eq!(queue.peek(), Some((3, "c")));

Currently this requires to either peek and pop:

while let Some((k, _)) = queue.peek() {
    if k < 3 { 
        break 
    }

    let Some((k, v)) = queue.pop().unwrap();
} 

Or constant pops() with a push of the removed item which does not match the predicate.