Allow Enumerables to be used with "where" filter.
where filter - test return value when filtering a Hash
Utils.slugify: Don't create new objects when gsubbing
Add FormKeep to resources as Jekyll form backend

Launched by [thoughtbot] today.
Intended to be Jekyll-friendly with
no iframes, JavaScript embeds, or CSS overrides.
It just generates a URL to use as your form's `action` endpoint.

It has a very simple webhook system, which means
it can automatically forward all submissions to a webhook of your choosing.
We've been using [Zapier] to handle the heavy lifting of
sending form data along from FormKeep to MailChimp, Trello, etc.

[thoughtbot]: https://thoughtbot.com
[Zapier]: http://zapier.com
Merge pull request #3010 from croaky/master
Update history to reflect merge of #3010 [ci skip]
Docs: Clarify behavior of 'categories' in permalinks
Revert "Make permalink parsing consistent with pages"
Merge pull request #3013 from jekyll/revert-2921-post-dest
Update history to reflect merge of #3013 [ci skip]
 Hash#each_key instead of Hash#keys.each. Faster code.
Merge pull request #3017 from glaucocustodio/master
Update history to reflect merge of #3017 [ci skip]
Merge pull request #3011 from fhemberger/master
Update history to reflect merge of #3011 [ci skip]
Merge pull request #2986 from tamagokun/where_filters_enumerable
Update history to reflect merge of #2986 [ci skip]
Merge pull request #2997 from jekyll/utils-slugify
Update history to reflect merge of #2997 [ci skip]
Sort webrick_options