Optional dependencies/Behaviour-based 'tools'?

[amokan]

Given that the crawling effort was merged in (which adds deps for :floki and :crawly) and the existing :abacus dependency, is there a planned effort to make these sorts of deps optional and maybe implement some sort of behaviour to facilitate making things more flexible for consumers of the project?

I'd be willing to help on this if there is interest.

Nothing at all wrong with any of the deps, but not every use-case will need them.