ENH: Replaced integer cast rounding methods with built in rounding functions.

[kian-weimer]

Using (int)(double_expression + 0.5) to round can be inaccurate and slow. Similar usages have been replaced with lround. This implements the bugprone-incorrect-roundings clang-tidy check. -"Casting (double + 0.5) to integer leads to incorrect rounding; consider using lround (#include ) instead"