Adopt MoonTool formula for calculating moon phase

[mannylopez]

Closes #27 [AstronomicalConstant] Calculations off by ~4.5hrs

Big refactor to remove most of the functions from sunCalc in favor of code from Moontool for Windows. The original code is written in Visual C and I converted it to Swift and removed extra functions I don't need.

Not only is this more accurate, but it also provides more metadata, such as the age of the moon and distance to the moon.

Added a new MoonDetail object to house this data.

struct MoonDetail {
    let julianDay: Double
    /// Number of days elapsed into the synodic cycle, represented as a fraction
    let daysElapsedInCycle: Double
    /// Age of the moon in days, minutes, hours
    let ageOfMoon: (days: Int, hours: Int, minutes: Int)
    /// Illuminated portion of the Moon, where 0.0 = new and 0.99 = full
    let illuminatedFraction: Double
    /// Distance of moon from the center of the Earth, in kilometers
    let distanceFromCenterOfEarth: Double
    /// Phase of the Moon, represented as a fraction
    ///
    /// Varies between `0.0` to `0.99`.
    /// `0.0` new moon,
    /// `0.25` first quarter,
    /// `0.5` full moon,
    /// `0.75` last quarter
    let phase: Double
  }

This does not break the API.

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Special thank you to the author of MoonTool, John Walker, for providing the source code.