Enable pagination in me.starred method

API would change to

```javascript
var github = require('./lib/octonode');

var client = github.client({
  username: 'xxxxxxxx',
  password: 'xxxxxxxxx'
});

client.me().starred(2, 30, function(err,data) {
  console.log(data);
});

client.me().checkStarred('slate/slate', function(err,data) {
  console.log(data);
});
```
Using the starred method to both fetch starred repositories and check if a repo has been starred adds complexity to the API. I think splitting into two method definitions is better: easier to test, can evolve independently