OpenXML Filter: provide the same capabilities to documents in the strict mode

[Denis Konovalyenko]

This is a follow up for issue #858. It has been revealed that a number of places depend on the namespace awareness, thus, the extraction and merging may differ from what is available for the documents in the transitional mode.

For more details please refer to the attached example.

[Denis Konovalyenko]

A related pull request #338, which provides a partial implementation, has been merged.

The following areas are still have to be addressed:

1. Powerpoint hyperlinks processing (hlinkClick and hlinkMouseOver)

2. Visio documents (most probably that would not be needed as such documents are not mentioned in the ISO/IEC 29500 spec)

3. Word styles parsing

4. Skippable elements processing (when some of elements are escaped under different conditions)

5. Complex fields processing

6. Shade run property processing

7. Excel styles parsing

8. Excel toggle properties handling

9. Powerpoint styles optimisation

10. Text body properties clarification

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[Denis Konovalyenko]

Related issue #1134.