Group pages within their own directory

Add `pages` as it's own content type, and move all page content into
the appropriate directory.

Any references to `layout` in the YAML front matter has also been
removed as it's implied by the content type. Except for `about.md`
which does explicity use a different layout.

source/_pages/stream.md

@@ -0,0 +1,15 @@
+---
+title: Live Streaming
+---
+I like try and do some live coding when I can, whether I’m working on a side project, my own website or some open source code. You can find my [stream link on YouTube][0], or view some previous streams below:
+
+## Stream Playlists
+
+- [Miscellaneous coding live streams][1]
+{# - [Building the PHP South Wales website][2] #}
+{# - [Using PHP to generate Gmail Filter XML with the Gmail Filter Builder][3] #}
+
+[0]: {{site.youtube.stream.url}}
+[1]: https://www.youtube.com/playlist?list=PLHn41Ay7w7kcWbjrYaiqXlfrqi_teTJE8
+[2]: https://www.youtube.com/playlist?list=PLHn41Ay7w7keUxBa-6TNn0_xz27ZfLD5f
+[3]: https://www.youtube.com/playlist?list=PLHn41Ay7w7keRp47rXEx9his-oA8kk4-v