Potential fix for issue #102

This fixes my issue with collection check_boxes not showing their error messages properly.

The solution here is to wrap the form_group with bootstrap_wrapping
which will set the label in the "right" place AND add the error
message in the right place.

It's not clear to me why this set of elements wasn't getting wrapped with the bootstrap_wrapping call.  If it was intentional - then this fix might have issues in other contexts.