Sync zoneinfo database with tzdata2013b from ftp://ftp.iana.org/tz/releases

* africa: Morocco does not observe DST during Ramadan; try to predict
    Ramadan in Morocco as best we can. (Thanks to Erik Homoet for the
    heads-up.)

* northamerica: Haiti uses US daylight-saving rules this year, and
    presumably future years. This changes recent time stamps. (Thanks
    to Steffen Thorsen.)

* southamerica: Paraguay will end DST on March 24 this year. For now,
    assume it's just this year. (Thanks to Steffen Thorsen.)