More test and warning cleanup

Using assertions were possible.
Clear as many of remaining 'hiding' field warnings as possible.
Any donated code must comply to code base.  Fixing latest toString donation.
Deprecate base64 test as it was inadvertently changed to test guava which is all waffle now wraps until 1.8.
Re-introduction of tests to waffle-jna that are in waffle-test.  Keeping waffle-test for now as it likely tests more functional tests rather than just ring to get coverage.  Will review later.