Begin work on chapter 3
Fixed figures alignments
Uses minted 2 (alpha) with cache, and tabu.

Ignores additional cache files.
Continues work on Chapter 3

Int Types Table.
Minted listings
Minor rephrasing in the first two chapters.
New, third chapter.

This chapters deals with variable, constants and basic maths.
It also contains a short introduction to functions, from the user point of view.
Corrected typo in comment