OpenXML: Consecutive runs containing tabs can be incorrectly merged

[Chase Tingley]

The attached file contains some text with two embedded tabs, divided across multiple runs. The pattern looks like this:

<w:r>
  <w:tab/>
  <w:t>-</w:t>
</w:r>
<w:r>
  <w:tab/>
  <w:t>R</w:t>
</w:r>

Because the runs have the same properties, they are merged, but the tabs are ignored, so you end up with a single run like this:

<w:r>
  <w:tab/>
  <w:t>-R</w:t>
</w:r>

The result of this is that one of the tabs appears to disappear during translation.

[Chase Tingley]

Fix issue #467 - openxml filter could lose some tabs during extraction

→ <<cset acde79aeea03>>

[Chase Tingley]

Fix Issue 458, Fix Issue 467, and Fix Issue 473 in the openxml filter

This rewrites OpenXMLContentFilter.combineRepeatedFormat() and
splits out the markup simplification content to a new class called
ParagraphSimplifier.  This fixes many issues in the old code with
multiple <t> elements in a single run, as well as issues with tabs
and linebreaks that were being lost when interspersed with text.
This covers Issue 458 and re-fixes Issue 467 in a better way.

Additional fixes were to Issue 473 and an unfiled problem with
entities in deleted text that weren't being re-escaped in target
output.

This has caused some changes to placeholder creation in segments.

→ <<cset 2445b887857a>>

[Chase Tingley]

Fix Issue 458, Fix Issue 467, and Fix Issue 473 in the openxml filter

This rewrites OpenXMLContentFilter.combineRepeatedFormat() and
splits out the markup simplification content to a new class called
ParagraphSimplifier.  This fixes many issues in the old code with
multiple <t> elements in a single run, as well as issues with tabs
and linebreaks that were being lost when interspersed with text.
This covers Issue 458 and re-fixes Issue 467 in a better way.

Additional fixes were to Issue 473 and an unfiled problem with
entities in deleted text that weren't being re-escaped in target
output.

This has caused some changes to placeholder creation in segments.

→ <<cset 2445b887857a>>