Test whether the two rectangles are effectively the same.
Rectangles are considered equal if they have the same position,
width and height. This represents value equality for the rectangles
in question.
The underlying components of an XRect are represented as
floating point numbers. Floating point numbers are subject to
rounding errors, so there has to be a degree of latitude when
comparing coordinate values. The degree of latitude is, by default,
determined by the limitations defined in the PDF Specification.
This is, broadly speaking, 5 decimal points so the default epsilon
is typically 0.00001. However if you wish to rely on a specific
epsilon value you should provide one.
