* Fixes in CI (#406)
* Create .gitattributes
* Update .travis.yml
* Update .travis.yml
* travis fix
* only errors are printed in travis log
* spreadsheet errors fixed: duplicate ID in non-visual properties and lack of third axis in an example
* set-strict example fix
* build-examples.sh exits with error status in the case of build error
* redundant command deleted from script
* unneeded image relationships removed
* pptx validation errors fixes
* all output to travis
Co-authored-by: Gunnsteinn Hall <gunnsteinn.hall@gmail.com>
* 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