Moving Functionality to be on Fluent Type

I call these base types FluentTypes as all of the behavior of the type moves into the base type class.
Instead of newing up an IntegerEquality, we can now call IsEqual on our subject and compare it to our expected. This allows us much smoother and simpler interaction with the types.

AddTwoInts/AddTwoIntsTests.cs

@@ -15,17 +15,16 @@ public void ShouldReturnSumOfTwoInts()
             Integer subject = new Sum(augend, addend);
 
             //Act
-            Bool integerEquality = new IntegerEquality(subject, expected);
-
             //Assert
-            Assert.IsTrue(integerEquality);
+            Assert.IsTrue(subject.IsEqual(expected), $"Actual <{(int)subject}> was not the same as Expected <{(int)expected}>");
         }
     }
 
     public abstract class Integer
     {
         public static implicit operator int(Integer origin) => origin.Value();
         protected abstract int Value();
+        public Bool IsEqual(Integer other) => new IntegerEquality(this, other);
     }
 
     public sealed class IntegerOf : Integer