Remove SymLink Add Aliases (#26)

This PR reverts commit 6ad74b6 and instead adds the following under `content/post/_index.md`:
```
aliases = ["posts","articles"]
```

Basically the symlink from #24 duplicated all posts in theme demos, so it needs to be removed.

Aliases on the other hand thanks to the Netlify Redirect Output Format defined in the gohugoio theme over [here](4320e757c9/config.toml (L21-L31)) and [here](https://github.com/gohugoio/gohugoioTheme/blob/master/layouts/index.redir) become 301 redirects, so they hopefully offer a solution to the issue of the various themes using different sections in their demos that I described in https://github.com/gohugoio/hugoBasicExample/pull/24

content/post/_index.md

@@ -0,0 +1,3 @@
++++
+aliases = ["posts","articles"]
++++

content/posts

@@ -1 +0,0 @@
-post