NExpect.Matchers.NSubstitute NuGet Package

This library offers NSubistitute-specific extensions so you can have Expect-style
syntax for your NSubstitute assertions.

For example, one may previously have done:
```
Expect(result).To.Equal(expected);
someService.Received(1).SomeMethodCall();
```
and now you can keep it consistent:
```
Expect(result).To.Equal(expected);
Expect(someService).To.Have.Received(1).SomeMethodCall();
```.