Failure to ignore comments, now using tabs instead of spaces for indentation.

This is a follow up to my previous pull request [https://github.com/schorfES/grunt-lintspaces/pull/10/commits]. You (Norman) remarked that the failures where due to using spaces with the comments file rather than tabs. However, I'm able to reproduce when using tabs too (using the comments file as enclosed with this pull requests). Please advice,

Cheers,
Edwin