Here's the deal:

• The current Cursor class and its Iterator implementation can be deleted
• Copy over the isDead() implementation over to Result
• Result can simply be Traversable
  • IteratorAggregate was only used because we were going to support custom iterator classes (but no longer as of PHPC-214)
  • Internal classes can implement Travserable by having a get_iterator() handler. Down the line, a mongofill or userland clone of Phongo can simply implement Iterator or IteratorAggregate as needed to still work with PHPLIB.
• Result can now be renamed to Cursor (we still want that name)