Elixir implementation of Gregorian Date to Discordian Date conversion
utility mercilessly ripped from core-utils.

# Usage

    [red@aneristic ddate]$ iex -S mix
    Erlang/OTP 18 [erts-7.1] [source-2882b0c] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]

    Compiled lib/ddate.ex
    Generated ddate app
    Interactive Elixir (1.0.5) - press Ctrl+C to exit (type h() ENTER for help)
    iex(1)> Ddate.ddate
    "Sweetmorn, 14th of The Aftermath YOLD 3181"
    iex(2)> Ddate.ddate({2016,2,29})
    "St Tibs Day, YOLD 3182"