Update examples to use QPDFObjectHandle iterators
Update examples to use QPDFObjectHandle iterators

jberkenbilt/qpdf,qpdf/qpdf,qpdf/qpdf,jberkenbilt/qpdf,qpdf/qpdf,jberkenbilt/qpdf,jberkenbilt/qpdf,jberkenbilt/qpdf,qpdf/qpdf,qpdf/qpdf