require(ing) individual components

Did y'all consider doing this

```
var Checkbox = require('material-ui/Checkbox');
var EnhancedButton = require('material-ui/EnhancedButton');
```

instead of

```
var {Checkbox, EnhancedButton) = require('material-ui');
```

??

Seems that with this type of library you shouldn't be importing the pieces you don't need. 
