646 - Add less documentation to demo pages.

In this branch, I performed the following:

* Removed references to styleguide
* Added less documentation tab to the demo page

I will squash the commits once the PR is approved.
@klamping  Would it make sense to include something like:

```
The entirety of the Encore UI CSS is available via the main CSS file. To use, simply include it on your page.
```