switch to customized sass & don't loop

[naturallymitchell]

https://github.com/alexerlandsson/css-fadeshow#customized-installation
alexerlandsson/css-fadeshow#3

[naturallymitchell]

@LuisReyes98 , we should use Machu Picchu to include the library, instead of adding it to our repo

can you take care of it with the existing examples or do you need a hand?