OpenSystemsDevelopment / qpdf

This reverts commit ff2a78f579ebdd06b417e34260a17dba06e71137, reversing
changes made to 8f54319f7a6514110f4b05cbbf1cb1c9fc8cb6a0.

This reverts commit c648b9a018105a3c30b3e7f3c5f8a058d3ddd92c, reversing
changes made to 12b67a3227df6b6df3a4f5f098e11cce173ff7d5.

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.