* Update Lifting State Up not to mix up DOM value with component state
A few weeks ago when teaching my friend, she got stuck on
`this.state.value` vs. `event.target.value`. As the documentation
talked a lot about "values", and the term value could mean three
different things (values in general, the "value" prop / DOM value of
the <input> component and the value in state/props), it was not weird
that she got a bit confused.
* Rename Lifting State Up onChange props to onTemperatureChange
This is in-line with how the temperature is provided as a prop named `temperature`
* Fix one value prop not being renamed to temperature
* Update codepen examples in Lifting state up documentation
* Update devtools state change to reflect docs change
* Add more to Codebase Overview
* WIP
* Start a reconciler overview
* Add a few more sections
* todo
* WIP
* Finish it
* Whitespace
* Minor tweaks
* Minor tweaks
