LoadCultures() in LocalizationManager skipped all iso6392.txt entries
without a two-letter ISO 639-1 code, dropping 302 of 496 languages
including mul (Multiple languages), und (Undetermined), mis (Uncoded
languages), zxx, and many real languages like Achinese, Akkadian, etc.
This caused FindLanguageInfo() to return null for these codes, which
meant:
- ExternalPathParser could not recognize them as valid language codes
in subtitle filenames, so the Language field was never set
- DisplayTitle fell back to the raw code string (e.g. "Mul")
Fix by allowing entries without two-letter codes to be loaded with an
empty TwoLetterISOLanguageName. Also set LocalizedLanguage in
ProbeResultNormalizer for ffprobe-detected streams (the DB repository
path was already handled on master).
* Translate the ISO-639-2/B codes to ISO-639-2/T.
This enables 19 additional languages to be displayed correctly.
* Convert the 2-dimensional array to a dictionary
* Added the French language to the list of ISO-639-2/B codes
* Don't change the property, use a local variable instead.
* When creating the MediaStream in the MediaStreamRepository ensure that the ISO 639-2/T (f.e. deu) code is used for the language as that is the one the .NET culture info knows.
The other code is most likely the ISO 639-2/B code (f.e. ger) which is unknown to the .NET culture info and will result in just displaying the code instead of the display name.
* Move the substitution of ISO 639-2/B to /T to the localization manager.
Some language (like Chinese) have multiple entries in the iso6392.txt file (f.e. zho|chi|zh|..., zho|chi|zh-tw|...) but the conversation between /T and /B is the same so use .TryAdd.
* Change the method definition from GetISO6392TFromB to TryGetISO6392TFromB and return true if a case was found.
* Add unit tests for TryGetISO6392TFromB.
* Change the order of the ISO-639-2 list
Now the ISO 639-2/T (terminological) comes first (which is the same as the ISO 639-3 code) and the second column is for the ISO 639-2/B (bibliograpihc) code.
The terminological code is derived from the native name for the language while the bibliographic code is more of a "legacy feature" where the code is derived from the English name for the language.
The format of the file is now
ISO 639-2/T (or ISO 639-3) | ISO 639-2/B (where applicable) | ISO 639-1 (two-letter code) | English name | French name
* Sort the ISO list by the first column
