Add constructor specs around Page
specs for Page#content
specs for Page#get
specs for Page#title
spec Page#htmlPath
spec Page#fileName
spec Page#date
Merge branch 'page-spec'

* page-spec:
  spec Page#date
  spec Page#fileName
  spec Page#htmlPath
  specs for Page#title
  specs for Page#get
  specs for Page#content
  Add constructor specs around Page
Copy content over to destination (hardcoded).
Now generates the stuff in the `dest` folder

We have a problem, in that it's duplicating the dest folder.
Should be easy to track down though

```
Writing 10197 characters to
dist/dist/posts/2014-06-15-extending-d3js.html
Writing 10197 characters to
dist/dist/posts/2014-10-07-dac-blog/index.html
Writing 4793 characters to dist/dist/articles/an-article.html
Writing 23471 characters to dist/dist/help.html
Writing 5494 characters to dist/dist/search.html
Writing 11642 characters to dist/index.html
Writing 14533 characters to dist/posts/index.html
Writing 9868 characters to dist/index.xml
```
Works flattened or otherwise. Still needs more testing.

* Uses a second `WritesFile` because it expects all files to be relative. Not sure best way to fix yet, but have some options.
* Broke up the efforts in the main task a bit more.
Backwards compatibility seems to work for my repo. Could use a larger test set though.

* New `MaybePathLib` that handles non-string values getting passed into `path.join`
* Delete markdown file in place once converted
* Simplified getting the list of markdown files for processing
* A couple of tests aren't valid any more. Will have to discuss best way to replace them.
Removing some logging; don't need it.
I think the `htmlPath` will work for all cases, since it will already exist in the right place. If not, the copy is the place to fix it.
Added new `diskPath` to `Pages` and `Posts`

* `diskPath` and `htmlPath` are different now
* `htmlPath` will strip off any trailing `index.html`s. Consider matching other default pages, but not right now
* Broke a few tests, fixing that next.
Fixing until tests.
Add basic support for blog post category listings.
Use existing posts var