enable msvc wanring 4800

unlike the title suggests, this pr contains more then 'enable msvc wanring 4800'. this pr contains:
1) Enable msvc wanring 4800: after i recenty made a bug that broke move+attack (28ebde5741055) i believe this is a useful wanring, also there were some other bugs that wanring uncovered (but maybe in unused code?). This is done in commit 'enable msvc bool conversion check' (2a2c469).
2) We add a commandlaine option for precise timestamps (0a86c5c) maybe someone who knows better english then me could check the sentences?
3) some improvements in replay.cpp.