Feature/sphinx doc

[nvitucci]

This is a stab at converting the existing doc into Sphinx format. To achieve this, I:

• created a doc/sphinx/source folder via sphinx-quickstart;
• copied over the doc/source folder into doc/sphinx/source (excluding doc/source/bin);
• renamed all the .txt files to .rst (for clarity);
• removed the internal links files (e.g. source/knowledge_bases/links) by adding their links to the main links file (renaming them when necessary);
• removed the restindex and uservalues sections in each .rst file (replacing them with a toctree element in the inner index.rst files).

Once the new generated doc is checked, the doc/source folder can be removed.

[Mandroide]

Use an imperative tone to describe what a commit does, rather than what it did.

Source:
Udacity Git Commit Message Style Guide

[nvitucci]

Use an imperative tone to describe what a commit does, rather than what it did.

Source:
Udacity Git Commit Message Style Guide

Thanks for the suggestion, I will do that in the next commits. I would appreciate a review on the content as well.