Add support for reading <w:tab/> element in runs.

[zobo]

Description

Adds support for Word2007 reader to understand <w:tab/> element in <w:r>. All samples seen so far had only either w:tab or w:t elements. Encoded as "\t" character. This will still display correctly in MS Word, however a proper writer should also be implemented.

Related to #862 .

Checklist:

• I have run composer run-script check --timeout=0 and no errors were reported
• The new code is covered by unit tests (check build/coverage for coverage report)
• I have update the documentation to describe the changes

[troosan]

Hi @zobo w:tab is already supported (PhpOffice\PhpWord\Style\Tab), only indeed, the reader part is missing. Would you mind reading it as such instead of a simple /t?

[zobo]

Hi! Thanks for your comment. As far as I can tell from ECMA-376 there are two different w:tab elements. The one already defined in the code you refer to, I believe, is the one present in w:pPr/w:tabs . There is another w:tab element, defined in 17.3.3.32 chapter of Ecma Office Open XML Part 1 - Fundamentals And Markup Language Reference.pdf. This one doesn't have the same properties, however I couldn't find the relevant XML definition...
I noticed an example at the end of the chapter 11.3.9, page 50. It shows there that within one w:r there can be a combination of w:t and w:tab elements. I have changed the code to support such case.

If you thing a special element is needed anyway, I can try to figure out how to do that and define a different Tab class.

[troosan]

indeed, you are right. You are referring to http://www.datypic.com/sc/ooxml/e-w_tab-2.html