Fixed bug by appending rss.xml/index.atom after a url of BlogEntryView.

When user append 'rss.xml' or 'index.atom' after the url of a blog entry,
the app will cause error.

For instance, If there is a blog entry named 'test_entry' and user can
access to '/test_entry' and then user access to '/test_entry/index.atom',
the blog app will cause AttributeError due to try to access 'sdi_title' attribute
of 'Blog Entry' object.

So in this changeset, I applied 'context_type' setting to FeedView to ensure
the views appear on root of the site.
unused import
add 3.4 to supported versions
79 cols
Merge branch 'feedview_on_entry_bug' of github.com:hirokiky/substanced into hirokiky-feedview_on_entry_bug
Merge branch 'hirokiky-feedview_on_entry_bug'