add plusPeriod, minusPeriod functions add BusinessDayConventions add Calendar type and some calendars add Calendar related functions
add plusPeriod, minusPeriod functions
add BusinessDayConventions
add Calendar type and some calendars
add Calendar related functions

NunoEdgarGub1/hql,pcaspers/hql,pcaspers/hql,NunoEdgarGub1/hql