[pl] polish translations in makeebooks

Translated fields: figure caption, title, license comments
Merge pull request #428 from marianes/master

[pl] Polish translations in makeebooks
Look for a commit referencing a file in all branches

As pointed by @mutewinter, the command must look for the changes
to the file in all branches.

This change closes #170
Merge pull request #429 from progit/look_for_git.tbz2_on_branches

Look for a commit referencing a file in all branches