lowercase template function first to be consistent with all other template functions
Homepage now has all content available, use sorting and first to control rendering
Version bump 0.9
Updating docs to include ‘first’ functionality for the homepage
Updated release notes.
configurable permalinks support

A sample config.yaml for a site might contain:

```yaml
permalinks:
  post: /:year/:month/:title/
```

Then, any article in the `post` section, will have the canonical URL
formed via the permalink specification given.

Signed-off-by: Noah Campbell <noahcampbell@gmail.com>
Documentation updates, mostly for my bits

* extras/permalinks.md added, weighted to third in the extras menu
* examples added to layout/go-templates.md, using `.Site.Params`
* mention `.Site.Params` in layout/variables.md
* update meta/release-notes.md to mention `first` and the permalinks
* update overview/configuration.md to use reserved-for-documentation
  domains and with another example, nudging towards permalinks and site
  parameters, with three different data-types shown for the latter

Signed-off-by: Noah Campbell <noahcampbell@gmail.com>