Pkg: Research visual regression testing

[xak]

To enhance the standalone component test framework, we should include a visual regression test to easily identify when existing components have unexpectedly changed.

Basic reqs should include standalone testing and full CSS testing to ensure everything works individually but also ensure, more important, that other library additions are not introducing problems.

Look at:

• https://github.com/Huddle/PhantomCSS
• https://github.com/gemini-testing/gemini

[joseegm]

Maybe later on based on resources we have as stand alone project