Replace posts.reverse with posts.docs.reverse (deprecation)

[lukasschwab]

Minor change––the posts.reverse method is deprecated, and should be replaced with posts.docs.reverse.

Serving my Jekyll site when using this paginate package, I get repeated (13 times) deprecated warnings:

Deprecation: posts.reverse should be changed to posts.docs.reverse.
                    Called by /Users/lukas/.rbenv/versions/2.1.3/lib/ruby/gems/2.1.0/gems/octopress-paginate-1.1.2/lib/octopress-paginate.rb:136:in `collection'.

Not a crisis by any means, but I can't find documentation of a compelling reason to continue using the deprecated method! Made the change to the only instance it's called to get rid of the eyesore.

Tested using my personal site; resolved the warnings, found no issues. Let me know if I should test more rigorously.

Also, let me know if this warrants any other changes (e.g. versioning).

Thanks!

[lukasschwab]

My mistake, missed that this is covered here: #24

Closing... though there seems to be an issue with the test system!