Doesn't handle var statements with multiple declarations

I can't bulkify code that looks like this because static-eval is throwing:

``` js
var bulk = require('bulk-require')
  , _ = require('lodash')
  , conditions = bulk(__dirname, ['/*.js'])
```

However, this works:

``` js
var bulk = require('bulk-require')
var _ = require('lodash')
var conditions = bulk(__dirname, ['/*.js'])
```
