v2.2.0-beta6 (2.2.0.52297)

• Added serialization of the "source" property.
• Downgraded package dependencies to Microsoft.NETCore.App 1.0.1 level.
• Fixed the priority of getting an iKey from an environment variable
• Moved from PCL dotnet5.4 to .NET Core NetStandard1.5.
• Updated dependency versions.