When creating the original list of locales available to FreeCAD, also
scan the external directories and add those entries to the list of
locales. This enables the installation of a language pack in an
already-installed version of FreeCAD, allowing translators to test their
work more easily.
Add a hidden preference that will allow translators to add an entirely new
language to FreeCAD via user preferences, without requiring modification
of the FreeCAD source code.
Add a hidden preference for an additional translation directory.
* Updated the updateTranslations.py tool so it can now work with
unzipped folders, and it updates qt resource files when necessary.
* Updated existing translations, changed a couple of language codes:
es -> es-ES, pt -> pt-BR, zh -> zh-CN, se -> sv-SE
* Added new translations that have more than 50% translated:
cs, hu, ro, sk, zh-TW, tr
