OpenSystemsDevelopment / qpdf

It is common to just read a few objects. Checking extraction of the
first page exercises this to make sure we don't accidentally introduce
a change that makes that case worse, such as adding an unnecessary
traversal of the file, prematurely resolving objects we don't need,
etc.

A new private overload of QPDF::makeIndirectObject breaks pikepdf's
build, so renaming function.

…ternal2 and copyObject2

copyObject2 repeats a second time what
new_obj = QPDFObjectHandle(obj->copy(true))
in shallowCopyInternal2 already did.

…ternal2 and copyObject2

Have separate versions for unsafeShallowCopy, shallowCopy and makeDirect.

Add optional parameter shallow. Change logic errors to runtime errors.