Code Quality warnings reported in consuming projects

[markawightman75]

Describe the bug When using the SDK you get a set of build warnings relating to Microsoft.CodeQuality.Analyzers. These can be ignored but are confusing.

To Reproduce To reproduce:

1. Create a new Console app using .Net framework 4.7.2
2. Install the Waives.Http package, version 0.8.2
3. Compile

You will see a set of 163 warnings like this:

Expected behaviour You don't see any build warnings.

System details(please complete the following information):

• Visual Studio: Professional 2015, v 14.0.25431.01 update 3
• OS: Windows 10
• CLR and version: .NET Framework 4.7.2
• SDK version: 0.8.2
• VS NuGet Package Manager: 3.6.0

[alastairs]

We will not be providing support for VS2015 from 1.0.0-beta1 onwards

[alastairs]

We should ensure this is not an issue in VS 2017 and higher. I've removed references to VS2015 in the issue title and description.

[alastairs]

The warnings originally reported in the issue description screenshot are specific to VS2015 and so are out of scope for this issue. The library's code quality warnings are reported as follows:

Runtime	Visual Studio version	Checked	Warnings reported? (No ✅/Yes ❌)
.NET Framework 4.7.2	16.4 Preview 1	✅	✅
.NET Core 2.1	16.4 Preview 1	✅	✅
.NET Framework 4.7.2	16.3.1	✅	✅
.NET Core 2.1	16.3.1	✅	✅
.NET Framework 4.7.2	15.9.16	✅	✅
.NET Core 2.1	15.9.16	✅	✅

There is no more work required here.