Merge pull request #30 from FGM/master

Ltrim parameter error and typo
Add directory for french translation and only use Ubuntu fonts.
Chapter 0: About.
Chapter 0: Introduction.
Chapter 0: Getting started.
Chapter 1: The Basics.
Chapter 1: The building blocks.
Chapter 2: The data structures.
Chapter 2: Strings.
Chapter 2: Hashes.
Chapter 2: Lists.
Chapter 2: Sets.
Chapter 2: Sorted Sets, and summary.
Improved Makefile: PDF depends on its source and configuration file.
Use fonts available on Ubuntu. Fixes the PDF generation problem.