Vietnamese

[Shreeshrii]

Forwarding below some feedback re Vietnamese traineddata for 4.00.00

Vietnamese lang data for tess 4.00 seems to have better accuracy, but still sometimes mixes up between acute and hook above marks when they appear on top of circumflex mark (stack diacritics).

[Shreeshrii]

While testing some Seven Segment Display images, I noted that vie gives better result compared to eng.

[nguyenq]

With 4.00alpha vie language pack, many non-Viet alphabets appear in the output text, such as: öïäåů€†čµñÎīšçðßęě

[theraysmith]

Thanks! I will put them in forbidden_characters.