Allow use of NON_DEFAULT for POJOs without default constructor

[cowtowncoder]

Although it is necessary, ideally, to construct an instance of a POJO, to know what default values for properties are, current behavior of failing with exception in absence of zero-arg constructor is not optimal.
Instead it would make sense to just revert to "fundamental defaults", that is, nulls for objects and default values for primitives as excludable.

This change is mostly useful for using NON_DEFAULT as the global setting, where it is not possible to otherwise avoid possible exceptions for all types system handles. But it may also be slightly more useful than having to use NON_NULL or NON_EMPTY even when used directly on POJO.