small buttons are not vertically centered in a navbar

Created by: waynebrantley

A regular size button is properly vertically centered in a navbar:

<button type="submit" class="btn btn-primary navbar-btn" >
  Save
</button>

A xs button is NOT properly vertically centered in a navbar:

<button type="submit" class="btn btn-primary btn-xs navbar-btn" >
  Save
</button>

css fix:

.btn-xs.navbar-btn {
    margin-top: 12px;
}

(And this kind of thing most likely applies to other button sizes)