[it] update chapter2

Translate commit 60e2618
Deprecate google code downloads, point to sourceforge / github
As of current Git version, --all-match matches greps
[it] update chapter6

Reviewed "Git Tools"
[it] updating chapter6

Reviewed "Short SHA"
Merge pull request #738 from daftano/master

[it] update chapters 2 and 6
Merge branch 'progit/master' into ja