OpenSystemsDevelopment / qpdf

Also, delay adjustments for compressed objects until needed by
linearization checks.

Also, remove redundant clearing of the xref tabl during QPDF destruction.

Manual edits for cases not handled by search and replace

Using search and replace.

For consistency with similar methods, e.g. replaceObject.

Also, change test for QPDFObjGen::isIndirect to obj != 0.
Delete comment from commit afd35f9.

Change method signatures to use QPDFObjGen.
Use QPDFObjGen methods where possible.
Remove redundant QPDF::objGenToIndirect.

Change method signature to use QPDFObjGen.

Change method signature to use QPDFObjGen.

Rather than using object id -1 to mean "don't care", use object ID 0,
and clarify the difference between that use and indication of a direct
object.