Instead of having each page be an area of memory, where multiple
pointers to differing data may lie, we instead have each page being
one allocation. This ensures that a deletion algorithm, as provided,
would actually work without destroying older pointers which may have
been allocated. Great!
A page is a flexibly allocated structure of bytes, with a count of the
number of bytes already allocated (used) and number of bytes available
overall (available), with a pointer to the next page, if any.
heap_t is a linked list of pages. One may allocate a requested size
off the heap which causes one of two things:
1) Either a page already exists with enough space for the requested
size, in which case that page's pointer is used as the base for the
requested pointer
2) No pages satisfy the requested size, so a new page is allocated
which is the new end of the heap.
