Changed order of highlightning/unhighlightning

The reason: I have group of fields, with custom highlight/unhighlight 
function.
I add 'error' class to bootstrap 'div.control-group' on error.
So, if I have one field valid and one invalid in the same 'div.control-group',
all div by default will be valid, that is not expected behaviour.
I dunno, maybe these changes doesn't breaks things, so the only way is set showErrors option.