reorganization of the code into subfiles

1. saved the ‘static’ slides (e.g. the Sao Paulo presentation) in
slidesPikettyAll.tex

2. saved the dynamically created beamer frames containing figures,
together with the data setup, in slidesFigures.Rnw

3. still working on renaming the files automatically from
‘Figure_1_1-1.pdf’ to ‘Figure_1_1.pdf’ and so there’s a script at the
end of the ‘slidesFigures.Rnw’…