Add mode option for fade animations

OK so we are going to need to add the mode option with the carousel and gallery types. With carousel everything slides to the side, while gallery uses fade animations and changes all slides at once.

cedrichillion → made their first commit to this issue’s fork.

PR created with requested new Mode option.

Thanks @cedrichillion for your valuable contribution my friend!

Automatically closed - issue fixed for 2 weeks with no activity.