gpt : fix pytorch converter text encodings (#78)

gpt : fix pytorch converter text encodings (#78)

* Fixed quantization for f16 models not working - this is because the f16 tables were not initialized thus f16 to f32 conversion was failing.

* On some situations, the script fails with the error : UnicodeDecodeError: 'charmap' codec can't decode byte (byte) in position (number) : character maps to <undefined>
This is probably because the encodings are incorrect.
Explicitly specifying them as UTF-8 seems to resolve the issue and allow for correct conversion.

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Co-authored-by: Georgi Gerganov <redacted>