* [Translations/Localization] The Translation Editor plugin will now export TMX files with the proper XML DTD and header.  This makes the file more compatible with external translation tools.
* [Translations/Localization] When exporting multiple languages into a single TMX file using the Translation Editor, multiple languages are grouped for each distinct term.  A language without a translation for the current text will now include a blank value.  Previously, each language created redundant entries, and only languages with translations were included.  These issues confused some external translation tools.
Merge branch '6.8.7' into stable