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.
• [x] nodeRef API consistency (#159 / #272 )
• [x] Performance. No layout thrashing (no DOM reads in every cDU invocation, for instance)