0.5-4.2: Registers native routines per https://cran.r-project.org/doc/manuals/R-exts.html#Registering-native-routines

0.5-4.1: Upstream of the CRAN team's package maintenance efforts

0.5-4: Fix test so Windows build works.

0.5-3: License change, proper credit to authors of code used as a base for PCICt.

0.5-2: RESULTS CHANGE: Default gregorian calendar is proleptic; corrections applied are invalid. "Correction" code removed.
       Minor change: Add checking for calendar to operators.

0.5-1: API CHANGE: as.PCICt.numeric's argument order has changed
       RESULTS CHANGE: Modified code to make 360-day calendars have 12 30-day months.

0.4-1: Add support for proleptic gregorian calendar.

0.3-2: Fix off-by-one with Julian days.

0.3-1: Add min.PCICt and max.PCICt.

0.2-2: Actually export as.PCICt.POSIXct in the namespace. Whoops.

0.2-1: Cleaned up comments in code, added as.PCICt.POSIXct, added documentation for it, added more examples.

0.1-2: Initial version.
