Trigger compatibility mode on certain CSS components

[matthewmueller]

This PR helps ease the transition for Component users. This PR adds compatibility support for Components that have multiple styles or have CSS dependencies. Some of the Components that Duo should now support:

https://github.com/suitcss/theme
https://github.com/component/prompt-popover
https://github.com/component/prompt-popover
https://github.com/component/datepicker
https://github.com/component/dropdown
https://github.com/yields/select
https://github.com/yields/skeleton

Now, I'd like to remove this at some point, as it's a bit of a hack. But we'll need to come up with a good transition route to get everyone moved over.

Most of the tests are in css-compat. Head over there for more info.

Closes: #252

[matthewmueller]

Thanks for helping me sort through these issues @lancejpollard and @stephenmathieson !

[stephenmathieson]

nice!!

[ismay]

This is great! I've been having some issues with the suitcss components and their dependencies (like suitcss/base, which requires normalize.css), but now it all works as expected!