Added D65 Illuminant, minor improvements in XML documentation

Author: castarco

ColorSharp/ColorSharp.csproj

@@ -66,6 +66,7 @@
     <Compile Include="src\InternalUtils\Comparers.cs" />
     <Compile Include="src\InternalUtils\Structs.cs" />
     <Compile Include="src\ColorSpaces\ColorConversionStrategy.cs" />
+    <Compile Include="src\Illuminants\D65.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>
@@ -74,6 +75,7 @@
     <Folder Include="src\LightSpectrums\" />
     <Folder Include="src\MatchingFunctions\" />
     <Folder Include="src\InternalUtils\" />
+    <Folder Include="src\Illuminants\" />
   </ItemGroup>
   <ItemGroup>
     <None Include="packages.config" />