Feature/netcore preparation (#2035)

* Move to use package reference for restoring nuget packages.

* Return a task result for this async method.

* Update to a supported version of the .NET Framework. This also has the side effect of allowing us to automatically generate our binding redirects on build.

* Set the solution to target VS2017

* Update test solution csproj file to support being built through MSBuild 15

* Move to use package reference for restoring nuget packages.

* Return a task result for this async method.

* Update to a supported version of the .NET Framework. This also has the side effect of allowing us to automatically generate our binding redirects on build.

* Set the solution to target VS2017

* Update test solution csproj file to support being built through MSBuild 15

* DateTimeRoutines does not have Nuget packages that support .NET Standard (and therefore .NET Core). We will have to include them for now until we can get rid of this dependency.

* Move the interfaces into their own files. This will be useful when we share them between the .NET Core and .NET Framework WebAPI

* Stage services that need to point to the new interface namespace.

* Update CurlSharp to fix memory leak issue and support better runtime compatibility with OSX and Linux

* Start spliting some interfaces into their own files - this will help by allowing us to split them out in the future into a seperate project so the actual implementations can stay within their respective architectures when required

src/CurlSharp/Enums/CurlPipelining.cs

@@ -0,0 +1,21 @@
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+// 
+// Copyright (c) 2017, Dr. Masroor Ehsan. All rights reserved.
+// 
+// $Id:$
+// 
+// Last modified: 25.01.2017 1:23 AM
+// 
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+
+namespace CurlSharp
+{
+    /* bitmask bits for CURLMOPT_PIPELINING */
+
+    public enum CurlPipelining : long
+    {
+        Nothing = 0,
+        Http1 = 1,
+        Multiplex = 2
+    }
+}