refactored season length calculation for consistency
stop accounting for initial season
because new game initialization already sets us in the proper turn
some other random fixes
removed sun from night time
it was weird to have sunny nights, so I made sure that doesn't happen by adding a check (to the sun's wallet)
removed unnecesary typecasting
Prevent switch fallthrough that made spitters invincible to guns, smoke, and knives.
Merge branch 'weird-weather-removal' of https://github.com/WillyGalleta/Cataclysm-DDA into merge2

Conflicts:
	src/weather_gen.cpp

Looked straightforward.
Merge branch 'uninvincible-spitters' of https://github.com/kevingranade/Cataclysm-DDA into merge2
Merge branch 'master' of https://github.com/CleverRaven/Cataclysm-DDA into merge2
adjust for the cata year starting in spring
since the cata year starts in spring, we have to add that difference once so time is a constant and not dependant on wether you want to believe in it or not
Merge branch 'master' of https://github.com/CleverRaven/Cataclysm-DDA into merge2
Merge branch 'weird-weather-removal' of https://github.com/WillyGalleta/Cataclysm-DDA into merge2
Removes the bugcheck line.