Add optional transitions

[ghost]

First of all, good work. Minimal slide framework that just works. I only miss the transitions between li elements of ul or ol.

For the other hand, can you put more soft transitions among slides while we press the -> arrow? (alà deck.js)

Thanks in advance, Xan.

[briancavalier]

Thanks @somenxavier! That would definitely be useful. I'll look into it.