twbs/bootstrap — pull request #9821 by eratzlaff (2013-08-19 04:28:14+00:00)
Title: make visible/hidden classes mixable

Change on responsive-utilities for hidden and visible to be mixable
example:
`class="visible-xs visible-sm"`
test on mixins
example:
```CSS
.hide-xs-sm {
.hidden-xs;
.hidden-sm;
}