Nuclear War Simulator - Build 258 Beta Bugfix Update

- Bug fix: increased the country index map resolution to match the resolution of the population density map. This should eliminate some of the fatalities counting inconsistencies in small countries
- Bug fix: fixed two errors in the calculation of the biological effects terms. The calculated dose is now lower than before the fix
- Bug fix: changed all bearing angles to the widely accepted convention: clockwise angle with zero direction North