A PDF indirect object.
PDF supports a number of basic types of object. Objects may be
labeled so that they can be referred to by other objects. This type
of object is called an indirect object.
ABCpdf uses a slightly different terminology to avoid clashes
with other namespaces. Objects without labels contain basic data
elements and are referred to as Atoms.
The term 'indirect object' is often shortened to 'PDF object' or
sometime simply 'object'. There are a variety of types of PDF
objects from content layers to fonts to annotations. Every object
contains an Atom which represents the data held by that object.
Indirect objects are held in an ObjectSoup. This is a
non-traditional collection with some of the characteristics of an
Array and some of a Dictionary.
Implements: ICloneable, IDisposable