Merge pull request #532 from jugglinmike/move-tests

Move tests for `contains` method
Remove unused API method references
Remove unused variables from unit tests
Remove unused internal variables
Disallow unused variables
Remove aliases for exported methods

Prefer accessing these methods via the global `module` namespace for
clarity.
Merge pull request #533 from jugglinmike/unused

Remove unused variable references
Use JSHint's `extends` option

This allows the linting rules to be slightly more strict--test
environment globals should only be considered valid for test files.
Merge pull request #534 from jugglinmike/stricter-linting

Use JSHint's `extends` option
Move unit test files

Mirror the source code file structure in the unit test organization.