classify/cluster: Replace Emalloc by std::vector
classify/cluster: Replace Emalloc by std::vector

This should fix a warning from LGTM:

    Multiplication result may overflow 'int' before it is
    converted to 'unsigned long'.

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

stweil/tesseract,UB-Mannheim/tesseract,amitdo/tesseract,jbarlow83/tesseract,amitdo/tesseract,stweil/tesseract,stweil/tesseract,tesseract-ocr/tesseract,amitdo/tesseract,tesseract-ocr/tesseract,UB-Mannheim/tesseract,tesseract-ocr/tesseract,stweil/tesseract,jbarlow83/tesseract,amitdo/tesseract,amitdo/tesseract,tesseract-ocr/tesseract,jbarlow83/tesseract,jbarlow83/tesseract,UB-Mannheim/tesseract,jbarlow83/tesseract,UB-Mannheim/tesseract,tesseract-ocr/tesseract,stweil/tesseract,UB-Mannheim/tesseract