Add bootstrapped queues?

I still don't know how bad the extra internal laziness suggested in #115 might be, but it got me thinking: a strict version of that (i.e., strict in keys and values) would be perfect for implementing a relatively compact bootstrapped MinQueue. And adding a lazy value field in BinomTree yields a half-strict 2-valued queue perfect for implementing a bootstrapped version of MinPQueue. I've written up the basic operations, as well as unordered maps and traversals for the second version. I haven't done any benchmarking yet. Intuitively, I would expect this to be a little slower than our current queues, but likely faster than the bootstrapped skew binomial ones in the heaps package.

So do such queues belong here? There? Their own package?

The issue does not name files or tests. Start by reviewing #115, the current queues, and the bootstrapped skew binomial queues in the heaps package; compare the proposed strict and half-strict operations and determine where the new queue implementations should belong. Done requires an agreed package location and a defined implementation scope.