Update variable name and doc type to be accurate

Test Plan: Crossed fingers.
Finish renaming renderComponent -> render

Test Plan: jest
Merge pull request #2581 from spicyj/rm-elt-docs

Update variable name and doc type to be accurate
Merge pull request #2582 from spicyj/rendercomponent

Finish renaming renderComponent -> render
Add example for how to use `style` properly

Test Plan: jest
Merge pull request #2583 from spicyj/style-example

Add example for how to use `style` properly
react.js conf updates
better wording thanks to @jwalke
Mention that talks will be recorded
Use warning module for context warning instead of invoking console.warn and monitorCodeUse directly.  Depends on https://phabricator.fb.com/D1695279