Testing: Move to single harness page
Country Content: Update tests and demos

The country code is not appended as a class, but was had a test that had
that assumption. Updated the demos to clarify this.
Fixed some of the data-ajax test
Removed duplicate mocha stylesheet
Added ability to provide a folder for test fixtures
The content of any test folder will be copied over to be used by tests
Fixed the remaining data-ajax tests
Fixed by providing a different ajax content fixture
Exclude the test page from HTMLLint
Fixed the toggle test suite conflicting with mocha
Fixed the data-picture test cases
Merge pull request #5677 from LaurentGoderre/pull-5292

Move to single harness page