Fixed unit tests and implementation.

VolumeTests.cs had bad constants, implementation OK.
Unit.cs had bad constants for angle radians and gradians, so effectively a bad implementation. Tests were OK.

Author: angularsen

Src/UnitsNet/Generated/Angle.generated.cs

@@ -43,12 +43,12 @@ public Angle(double degrees) : this()
 
         public double Gradians
         {
-            get { return Degrees/1.11111111111111; }
+            get { return Degrees/0.9; }
         }
 
         public double Radians
         {
-            get { return Degrees/0.0174532925199433; }
+            get { return Degrees/57.2957795130823; }
         }
 
         #endregion
@@ -67,12 +67,12 @@ public static Angle FromDegrees(double degrees)
 
         public static Angle FromGradians(double gradians)
         {
-            return new Angle(gradians*1.11111111111111);
+            return new Angle(gradians*0.9);
         }
 
         public static Angle FromRadians(double radians)
         {
-            return new Angle(radians*0.0174532925199433);
+            return new Angle(radians*57.2957795130823);
         }
 
         #endregion

Src/UnitsNet/Unit.cs

@@ -110,9 +110,9 @@ public enum Unit
         [Area(0.00064516, "SquareInches")] SquareInch,
 
         // Metric
-        [Angle(Math.PI / 180.0)] Radian,
+        [Angle(180 / Math.PI)] Radian,
         [Angle(1)] Degree, // Base unit
-        [Angle(1 / 0.9)] Gradian,
+        [Angle(0.9)] Gradian,
 
         // Metric
         [Volume(1e9)] CubicKilometer,

Tests/VolumeTests.cs

@@ -60,12 +60,12 @@ protected override double CubicYardsInOneCubicMeter
 
         protected override double DecilitersInOneCubicMeter
         {
-            get { return 1E5; }
+            get { return 1E4; }
         }
 
         protected override double HectolitersInOneCubicMeter
         {
-            get { return 1E4; }
+            get { return 1E1; }
         }
 
         protected override double ImperialGallonsInOneCubicMeter