[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
[it] updating chapter6

Reviewed "A SHORT NOTE ABOUT SHA-1"
[it] fix error in formating
[it] fix remaining typos
[it] fix space at end of title
switch travis to parallel ci check
travis: add e-mail notification on status change
Apply 60e2618 to ja tree
Apply c418e2e to ja tree
Apply 44936fd to ja tree
Apply 3f6c105 to ja tree
Merge pull request #739 from harupong/update-ja

[ja] Update translation
[nl] Synchronized translation with SHA-1 3c18779
Merge pull request #742 from Cpt-xx/synchVersions

[nl] Synchronized translation with SHA-1 3c18779
update `git reflog` output to current one