allow to pass :views_prefix to #paginate to make kaminari work in cells.
add a test for :views_prefix.
move path logic to Tag#partial_path. allow to override the entire path segment using :views_prefix.
add README section about :views_prefix.
Merge pull request #552 from apotonick/views-prefix

Add views_prefix Option For Alternative Views Directory
Always put 'kaminari' into the partial path
Move template to spec/fake_app/views

I believe this template has been added for testing reasons, so I just
moved it to spec/fake_app/views.