OpenSystemsDevelopment / qpdf

Keep a std::pair internal to the iterators so that operator* can
return a reference and operator-> can work, and each can work without
copying pairs of objects around.

Add constructors that take a QPDF object so we can issue warnings and
create new indirect objects.

Create a computationally and memory efficient implementation of name
and number trees that does binary searches as intended by the data
structure rather than loading into a map, which can use a great deal
of memory and can be very slow.