Abort LSTM training with integer model (fixes issue #1573)
Abort LSTM training with integer model (fixes issue #1573)

Tesseract currently cannot continue LSTM training from an
integer (fast) model.

Report this to users who try it nevertheless instead of crashing
with an assertion.

Signed-off-by: Stefan Weil <8d4c780fcfdc41841e5070f4c43da8958ba6aec0@weilnetz.de>

tesseract-ocr/tesseract,amitdo/tesseract,UB-Mannheim/tesseract,UB-Mannheim/tesseract,stweil/tesseract,stweil/tesseract,UB-Mannheim/tesseract,UB-Mannheim/tesseract,stweil/tesseract,stweil/tesseract,amitdo/tesseract,tesseract-ocr/tesseract,tesseract-ocr/tesseract,stweil/tesseract,amitdo/tesseract,tesseract-ocr/tesseract,tesseract-ocr/tesseract,amitdo/tesseract,amitdo/tesseract,UB-Mannheim/tesseract