[ja] Apply 90c92ce
Translated the "Getting Started" section

The old translation was terrible. Filled with bad language and typos. I have started from the beginning, pasting in the english version of the file.
Translated the "About Version Control" section
Merge pull request #544 from harupong/ja-chapter8

[ja] Apply 90c92ce
Merge pull request #545 from fenre/patch-1

Translated the "Getting Started" section
Merge branch 'progit/master' into ja