If a file named index.html exists in a directory, or root, it will be
rendered as if ugly urls are turned on. This allows for top level
content to not need a supporting layout file and content in content.
This change should not affect anyone who is using the perscribed way.
I also cleaned up a bunch of one off functions in site.go.
I want to move all logic to writing aliases to target so I can pave the
way for writing aliases specific to other runtimes (like .htaccess for
apache or a script for updating AWS or symlinking on a filesystem).
Introducing the target module in hugo. This provides the simple
interface for writing content given a label (filename) and a io.Reader
containing the content to be written.
If site.Target is not set, it defaults back to the original behavior of
writing to file system.
In hugolib/site_url_test.go I have an InMemoryTarget for testing
purposes and use it to see if the final output of a render matches.
