v1.0.0 Quality Audits

[jamesplease]

Before we release v1.0.0, I would like to do an audit of the lib, checking for:

• CSS variable name consistency. I should be able to write down an algorithm for our CSS variable names, and ensure that every component adheres to it.
• rem usage vs px. Everything should be sized based on rem, so that as a user changes their browser font size, the Materialish components scale accordingly
• minimum React version. what version do we want to support? Maybe we should have a simple test that tries and renders each component in that version to ensure that we don't use incompatible APIs. Or maybe the website should use that minimum version. (The website needs to remain on the latest so that folks can use the latest APIs in the examples)
• Accessibility. Although v1 will not meet any specific accessibility standard (that will come post-v1), we should just make sure that we aren't doing anything really silly.
• nodeRef API consistency (nodeRef #159 / Supporting refs for internal and external use #272 )
• Performance. No layout thrashing (no DOM reads in every cDU invocation, for instance)