Merge pull request #1 from guygrigsby/master

pulling to update my fork
revised Thing42orNull interface
Merge pull request #5 from trevorsmith86/master

Resolve merge conflicts for stronger typing
Merge pull request #4 from robertzas/master

revised Thing42orNull interface
removed ? from tests
added unchecked -Xlint to compile switches
Merge branch 'master' of github.com:guygrigsby/Thing42
Merge pull request #6 from Menendez-Oscar/master

Merge pull request #1 from guygrigsby/master
fixed compiler warnings for java 8
Merge branch 'master' of github.com:guygrigsby/Thing42
put overrides back
Add tests for hashcode and equals
Merge pull request #7 from trevorsmith86/unit-tests

Add tests for hashcode and equals
Documenting the tests
Finish documenting tests
Merge pull request #8 from trevorsmith86/documenting-tests

Documenting tests
fixed hascode to include data and key