[pl] translation of section 9.3
Correct Typo
Merge pull request #465 from Rabierre/master

Correct Typo
Merge pull request #464 from gibas/09-git-internals

[pl] translation of section 9.3
[pl] translation of section 9.4
[pl] translation of section 9.5
Merge pull request #466 from gibas/09-git-internals

[pl] translation of sections 9.4 and 9.5