Rename deprecated bower component.json file to bower.json

I got a warning when installing via bower:

```sh
bower                       deprecated You are using the deprecated component.json file
bower underscore#~1.4.4         cached git://github.com/jashkenas/underscore.git#1.4.4
bower underscore#~1.4.4       validate 1.4.4 against git://github.com/jashkenas/underscore.git#~1.4.4
```
```sh
# My bower version:
$ bower -v
1.2.8
```

Renaming `component.json` to `bower.json` fixes this.