Running src/cli.js prints undefined

I tried to follow the example from the readme to render a template. Based on reading the code of `src/cli.js` it seems like the correct invocation is e.g., `node src/cli.js test/templates/simple2.htl`

### Expected Behaviour

The rendered template getting printed.

### Actual Behaviour

htlengine prints 'undefined'

### Fix

I found that changing line 50 in `src/cli.js` to `console.log(ret);`, i.e., removing the `.body` property access fixes the issue.

Cheers,
leeN