#22 Reviewed "Piwik on the Command Line"

#22

Previously, in the menu:

- User Interface
     - Pages
     - Menus
     - …
- Piwik on the Command Line

I've renamed that to:

- Web Interface
    - …
- Command Line Interface

I think this is more consistent and explicit: Piwik offers several interfaces (web, CLI, HTTP API…), plugins can code extensions to those interfaces.

We could even extend that to the HTTP Reporting API guides?

- Web Interface (controllers, views, pages, menus, …)
- HTTP API (Piwik APIs, Reporting API…)
- Command Line Interface

That conforts me that the current `MVC` guide with sub-guides:

- Models (API classes)
- Controllers
- Views

should no longer exist. "Controllers" and "Views" duplicates the "Pages" guide for example. Same for "Models (API classes)" with duplicates/confuses with the "Piwik's Reporting API" guide.

Anyway, this is for another pull request…