This class represents the bin table of Word document but it also serves as a
holder for all of the paragraphs of document that have been loaded into
memory.
DANGER - works in bytes!
Make sure you call getStart() / getEnd() when you want characters
(normal use), but getStartByte() / getEndByte() when you're
reading in / writing out!
A special (and dangerous) kind of Record Atom that cares about where
it lives on the disk, or who has other Atoms that care about where
this is on the disk.