review if it makes sense to make null value diffing optional

[SierraGolf]

currently null values are always rendered. it may or may not make sense to disable diffing and rendering of null values.

the main question is if the behaviour is except-able specifically in the use case of changing a value from null to non-null and vice-versa.

current output for null to non-null change

...
-SomeObject.property=null
+SomeObject.property='foo'
...

current output for non-null to null change

...
-SomeObject.property='foo'
+SomeObject.property=null
...

future output for null to non-null change with null rendering disabled

...
+SomeObject.property='foo'
...

future output for non-null to null change with null rendering disabled

...
-SomeObject.property='foo'
...