Update .travis.yml
Remove the unused `grunt-contrib-nodeunit` module and update the rest.
Revert f452db1bb09a71b9782edeb4a21c75ae049ede74.

The validator doesn't choke anymore on this and even though it's not spec compliant, it's needed for some IE versions. So until we move favicon.ico in root, this should do the job.
Clean up validator suppressions.
Use plain `if/else` statements when there's no assignment.
Switch to `(function){..})()`.
Remove JSHint's `expr` rule.
Minor style changes.
Run `grunt`.