Renamed Heap to Max Heap; fixed weaknesses in Binomial Heap description.

Indicated that the Heaps shown are Max Heaps, so that the
description of the operations makes sense.

Fixed Binomial Heap description to be more comparable with
Fibonacci Heap description:

  * Indicated amortized complexities where appropriate.

  * Allowed Binomial Heap to use the same max-tracking
    pointer that the Fibonacci Heap uses.