Added set of functions that perform integer division with different
rounding modes:
- divideAndCeil - rounds up to next integer
- divideAndRound - rounds to nearest integer
- divideAndFloor - rounds to previous integer (equivalent to default
division)
Intended for use in library, where usage of floating point might lead to
desync in multiplayer games.
Replaced some cases that I knew of, including recent handicap PR
81e6207df0