Add support of component.json

Here is a manifest file.
Keep it in the master branch and in releases tag, as described here: https://github.com/ractivejs/ractive/issues/1181

I've added `ractive` dependency, but haven't add `Backbone` to allow users decide between original `Backbone` and `exoskeleton`.
`component` users should know this simple trick:
```JS
require.define("backbone", require("exoskeleton"));
```

Also there is some issue with `component` itself, it can't handle your js-style and requires explicit aliasing for all dependencies. Here is the PR about it: https://github.com/visionmedia/node-requires/pull/9