Issue #1373: OpenXML Filter: PPTX: merged document corrupted over the appearance of an incomplete initial run before a line break (okapiframework/okapi)

[DenisKonovalyenko]

New issue 1373: OpenXML Filter: PPTX: merged document corrupted over the appearance of an incomplete initial run before a line break
https://bitbucket.org/okapiframework/okapi/issues/1373/openxml-filter-pptx-merged-document

Denis Konovalyenko:

The issue is reproducible under `bPreferenceAddLineSeparatorAsCharacter` condition set to `true`.

When a translation is leaded by a `\n` character \(or any other specified by the `sPreferenceLineSeparatorReplacement` parameter\), the following structure shows up:

```xml
<a:p>
<a:r>
</a:r>
<a:br/>
```

This is not allowed, according to the specification and has to be improved to contain an empty text:

```xml
<a:p>
<a:r>
<a:t></a:t>
</a:r>
<a:br/>
```

A sample document can be found attached.