The word "style" in API is confusing

I'm digging into `react-motion`, and I find using the word "style" in the API and documentation _very_ confusing.

Let's start with the opening example from readme:

```
import {Motion, spring} from 'react-motion';
// In your render...

{value =>

```

There is no styling animation here at all. And it takes time and frustration to figure out why this "style" doesn't style anything, has no relation to stylistic appearance, and still is called "style".

The way I see it, `react-notion` basically "springs" stuff, and the stuff does not have to be CSS styles. So there should be a better word for reflecting this purpose of the library (if I get the purpose right).

The same confusion applies to `TransitionStyle` objects and pretty much all the `*style*` names.

Maybe "motion" could be a better word, as it reflects the fact that ``, `` and `` take some static props and bring them to motion for their children. Any other suggestions are welcome.

I create this issue to see if someone else feels the same and consider renaming before the library reaches 1.0.

Start with the opening example in the README and review the API names mentioned in the issue, including Motion, StaggeredMotion, TransitionMotion, and TransitionStyle. No source files or tests are named; the work would be complete only after the project agrees on replacement terminology and applies it consistently across the API and documentation.

Written by the indexing model from the issue text.