Summary:
My benchmarks have shown react-emotion to be faster than the current implementation of `styled`. For this reason, I am converting all styling to [emotion](https://emotion.sh).
Benchmark results:
{F136839093}
The syntax is very similar between the two libraries. The main difference is that emotion only allows a single function for the whole style attribute, whereas the old implementation had functions for every style-attirbute.
Before:
```
{
color: props => props.color,
fontSize: props => props.size,
}
```
After:
```
props => ({
color: props.color,
fontSize: props.size,
})
```
Reviewed By: jknoxville
Differential Revision: D9479893
fbshipit-source-id: 2c39e4618f7e52ceacb67bbec8ae26114025723f
