Allow indentation in styleguide comment block

Rebased #57. In that ticket, @jpolete said:

We use block-style comments with indentation like this:

```
/*
  Some style

  Styleguide 1.1
*/
```

The parser doesn't pick up this reference because of the leading whitespace before "Styleguide". I just added a simple .trim() so comments like this won't get skipped.