Nth PR on develop branch for easybuild-docs, for N=9

latest yield
break this up, the `Contents` section is now pretty much meaningless in the TOC (note: you'll need to fix a ref to Contents somewhere, in the `Typical workflow` section I think):

```
Introduction
========

* What is EasyBuild?
* Concepts and terminology
   * EasyBuild framework
   * Easyblocks
   * Toolchains
   * Easyconfig files
* Typical workflow example: building and installing WRF
   * ...

Getting started
=========

* Installing EasyBuild
   * ...
* Configuring EasyBuild
   * ...

Basic usage topics
============

* Using the EasyBuild command line
   * ...
* Writing easyconfig files: the basics
   * ...
* Understanding EasyBuild logs
   * ...
```