Cannot make stack larger

[robsch]

FAS::stack()
  ->on(FAS::icon(FAS::_CIRCLE)->size(FAS::SIZE_3X))
  ->icon(FAB::icon(FAB::_TWITTER)->inverse()->size(FAS::SIZE_3X))

The circle does not get bigger. AFAIK the Stack::__toString() method does not allow such changed. Stacks work only with a single size. How can I enlarge the stack the right way? I would suggest the feature to set the size of a stack as well: e.g. with

FAS::stack()->size(FAS::SIZE_3X))
  ->on(FAS::icon(FAS::_CIRCLE))
  ->icon(FAB::icon(FAB::_TWITTER)->inverse())

The icon should be one size smaller than the circle automatically.

Also inverting the icon could be done automatically.

[rmrevin]

Hey. I apologize for the long answer. Welcome to pull request.