intproto: Use more efficient float calculations for floor
intproto: Use more efficient float calculations for floor

This fixes warnings from LGTM:

Multiplication result may overflow 'float' before it is converted
to 'double'.

While the floor function always calculates with double, here the
overloaded std::floor can be used to handle the float arguments
more efficiently.

Replace also old C++ type casts by static_cast.

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

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