Adapt StaticFile for collections, config defaults

[mbland]

This enables files such as images and PDFs to show up in the same relative output directory as other HTML and Markdown documents in the same collection.

It also enables static files to be hidden using defaults from _config.yml in the same way that other documents in the same collection and directories may be hidden using published: false.

Extracted from 18F/hub#332.

cc: @afeld @gboone @jeremiak @dhcole

[envygeeks]

I like it 👍

[mbland]

@envygeeks Thanks for the rapid feedback. All comments incorporated!

[envygeeks]

Do you mind rebasing the two commits into a single commit and forcing it up again so that other reviewers can see both the changes and everything in on swift review? Thanks!

[mbland]

No problem! Done.

[dhcole]

Nice work @mbland. Would be great to see this land in Jekyll core.

[parkr]

this is effectively @url.gsub! – why not use the bang method here?

[mbland]

Done.

I must've been thinking about how gsub! will return nil if nothing was changed, and how that would not work as a return value. But it's not a return value here.

[parkr]

Looking pretty good! Thanks, @mbland.

Looks like you're coming from a Python background, based on all those self.'s. In Ruby, we only use them when setting an attribute on a class instance, such as self.url = "some new url". When we access the attribute, however, we do not include the self. If you would please remove each instance of self. whenever accessing instance variables or methods, I would be most appreciative!

[mbland]

Thanks, @parkr! Took out all the self.s, though it's actually @afeld's fault I started using them in Ruby. :-P

[envygeeks]

Can you please rebase all this into a single commit so that it can be re-reviewed in one swift shot.

Thanks.

[mbland]

Yep! Done.

[parkr]

Cool!

[mbland]

Hey gang, not to nag, but is there further review pending, or is this ready to merge?

[envygeeks]

This is ready! Sorry I didn't notice @parkr said to

[mbland]

Sweeet, thanks, @envygeeks!