make mop remove blood, bile, slime and sludge fields and blood on cars

fix possible bug in field::removeField: don't increase iterator if point to end
Added support for 'OR'ing time conditions instead of having to create multiple entries for seasons and times.
check for curammo==0 in handle_liquid

set curammo in item constructor
Merge mop enhancements, monster time based spawn rule improvement, and handle liquid fix.
Merge branch 'master' of github.com:CuriousRaven/Cataclysm-DDA into dda-master