Added UV index and time

Author: sxg

Source/DataPoint.swift

@@ -107,6 +107,12 @@ public struct DataPoint {
     /// The columnar density of total atomspheric ozone at the given time in Dobson units.
     public let ozone: Float?
 
+    /// The UV index.
+    public let uvIndex: Float?
+    
+    // The time at which the maximum UV index occurs during the given day.
+    public let uvIndexTime: Date?
+    
     /// Creates a new `DataPoint` from a JSON object.
     ///
     /// - parameter json: A JSON object with keys corresponding to the `DataPoint`'s properties.
@@ -181,5 +187,11 @@ public struct DataPoint {
         pressure = json["pressure"] as? Float
         visibility = json["visibility"] as? Float
         ozone = json["ozone"] as? Float
+        uvIndex = json["uvIndex"] as? Float
+        if let jsonUVIndexTime = json["uvIndexTime"] as? Double {
+            uvIndexTime = Date(timeIntervalSince1970: jsonUVIndexTime)
+        } else {
+            uvIndexTime = nil
+        }
     }
 }