Default animations and classes to use them

[codysherman]

A lot of my projects end up having the same animations added to them. pop-in, fade-in, etc. Should they become a part of Frow (disable-able with a Sass variable of course)?

The classes would be able to be utilized as both calling animation: fade-in 1s as well as having quick reusable classes like .fade-in which would use the $animate-speed.