Verifies if "reference type" parameters are null

``` csharp
void Foo(Fee a)
{
}
```

becomes

``` csharp
void Foo(Fee a)
{
   if (a == null) throw new ArgumentNullException(nameof(a))
}
```

Style: `Refactoring`
Severity: `Hidden`
Id: `CC0078`

@clklachu is working on it.
