Implementing post creation.

- It now posts back to an Express route. Which fails, because I have no repository backing it.
Merge branch 'master' of github.com:rlipscombe/blog
Actually store articles; display them on the home page.

- Renamed TODO.md to TODO.wiki; this means that vimwiki will treat it as a TODO list.
- Actually save articles in MongoDB.
- Introduced settings file; moved blog title to it. Put MongoDB settings in there as well.
- Re-jigged the routes slightly, to cope with the home page.
- The home page now displays recent articles, with teasers, and pretty-printed dates.

Links:

- Pretty-printing timestamps: https://github.com/ecto/node-timeago
- Truncating HTML: https://github.com/huang47/nodejs-html-truncate
- Blog rolling with mongoDB, express and Node.js
Ignore temp/ folder.