Child icons font-size

[jayagl]

It's a very small thing, but I thought I should mention it.

There is no nice way to customise the size of the icons on child buttons using SASS without changing the whole button size, as it overwrites $icons-font-size used in .mfb-component__icon

.mfb-component__child-icon,
.mfb-component__child-icon{
  @extend .mfb-component__icon;
  line-height: $child_button_size;
  font-size: 18 / 56 * $child_button_size;
}

I just removed the font-size line to make it work for me.