* Regenerate code to handle purl.oclc.org docs correctly
* Make purl.oclc.org docs be opened just as the openxml ones
* Modify opening routine to change strict docs to non-strict
- `CustomXMLType` and `CustomXMLTypeStrict` were added to properly replace
these in strict docs
- `Decode` of `zippkg` was modified to replace the namespace in
relationships
- `TestOpenStrict` was modified to open the strict file, save it as
non-strict, reopen non-strict and validate its correctness
