Improve PropertiesComparer diagnostics

[chucker]

Can the PropertiesComparer return which property was unequal? It seems it currently fails without that information:

                        if (result == EqualMethodResult.ComparedNotEqual)
                            return result;

When a type has multiple properties, this only outputs the name of the type (or whatever ToString() happens to return), e.g.

Assert.That(result[0], Is.EqualTo(testData.ExpectedResult[0]).UsingPropertiesComparer())
  Expected: <MyTypeName>
  But was:  <MyTypeName>

[manfred-brands]

I improved the message, it not only says the failing property name, but also the value of that property:

Multiple failures or warnings in test:
  1)   Assert.That(new StructWithSomeToleranceAwareMembers(2, 1.1, "1.1", SomeEnum.One), Is.EqualTo(instance).UsingPropertiesComparer())
  Values differ at property StructWithSomeToleranceAwareMembers.ValueA
  Expected: 1
  But was:  2
    
  2)   Assert.That(new StructWithSomeToleranceAwareMembers(1, 1.2, "1.1", SomeEnum.One), Is.EqualTo(instance).UsingPropertiesComparer())
  Values differ at property StructWithSomeToleranceAwareMembers.ValueB
  Expected: 1.1000000000000001d
  But was:  1.2d
    
  3)   Assert.That(new StructWithSomeToleranceAwareMembers(1, 1.1, "1.2", SomeEnum.One), Is.EqualTo(instance).UsingPropertiesComparer())
  Values differ at propertyStructWithSomeToleranceAwareMembers.ValueC
  String lengths are both 3. Strings differ at index 2.
  Expected: "1.1"
  But was:  "1.2"
  -------------^
    
  4)   Assert.That(new StructWithSomeToleranceAwareMembers(1, 1.1, "1.1", SomeEnum.Two), Is.EqualTo(instance).UsingPropertiesComparer())
  Values differ at property StructWithSomeToleranceAwareMembers.ValueD
  Expected: One
  But was:  Two

If a property 3 levels down inside an array fails:

  Assert.That(two, Is.EqualTo(one).UsingPropertiesComparer())
  Values differ at property ParentClass.Two
  Values differ at property ChildClass.Values
      Expected and actual are both <NUnit.Framework.Tests.Assertions.AssertThatTests+GrandChild[2]>
      Values differ at index [1]
  Values differ at property GrandChildClass.Value
  Expected: 3
  But was:  4