kue.Job.rangeByState returns empty jobs array for non zero start index

kue.Job.rangeByState works as expected when i pass in Zero (based index) as its 2nd parameter
``` javascript
//Works as expected
kue.Job.rangeByState( 'complete', 0, n, 'asc', function( err, jobs ) {
jobs.forEach( function( job ) {
job.remove( function(){
console.log( 'removed ', job.id );
});
});
});
```
However any non-zero value seems to return a empty jobs array
``` javascript
//any non zero index 'i' makes the fun() return empty jobs array
kue.Job.rangeByState( 'complete', i, n, 'asc', function( err, jobs ) {
//jobs is an empty array
});
```

Start by reproducing kue.Job.rangeByState with a non-zero second argument and compare it with the documented zero-index case. Trace the rangeByState entry point and verify that the callback returns the expected jobs for non-zero start indexes while preserving the existing zero-index behavior.

Written by the indexing model from the issue text.