* 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
Decoding was getting fairly complicated, it seems cleaner
to have something handle the relationships file and traversal
and the document just be notified via callback when new
files have been found.
