Upgrade to FakeItEasy 4.6.0

[blairconrad]

Prerequisites

• [x] I have written a descriptive pull-request title
• [x] I have verified that there are no overlapping pull-requests open
• [x] I have verified that I am following the Nancy code style guidelines
• [x] I have provided test coverage for my change (where applicable)

Description

In FakeItEasy 4.4.0, we introduced a new API for asserting the number of times a call was made. We intend to replace the old Repeated mechanism with it, obsoleting the old way in 5.0.0, and removing it in 6.0.0. Rather than have you be surprised by this, I thought I'd convert all your assertions now. The Analyzer we released with FakeItEasy 4.5.0 detects usages of the old system and warns against them. It also contains a code fix provider to fix 'em all at once, so this was practically no work.

[blairconrad]

Hey, Folks!

I see we have a Travis build failure, but one that shows up sometimes. How concerned should I be? I tried to build in vagrant locally, but didn't even go so well as Travis did:

/vagrant/Nancy/.dotnet/sdk/2.1.4/Roslyn/Microsoft.CSharp.Core.targets(84,5): error MSB6006: "csc.dll" exited with code 137. [/vagrant/Nancy/test/Nancy.Tests/Nancy.Tests.csproj]

[blairconrad]

Thanks, @thecodejunkie!