Extend/improve "Diffing Binary Files" section v2

v2:
  * grammar fixes
  * description of img2txt is dropped
[ru] chapter 4: Improve wording in "Git Daemon" section
[fi] Translated Chapter 2.4
[fi] Made some improvements in Chapter 2.4
[pl] next part of the translation in chapter 7
	[nl] 	Delete english text
		Translation was already done
Merge pull request #486 from dwaddle/master

	[nl] 	Delete english text, translation was already done
Merge pull request #484 from gibas/07-customizing-git

[pl] next part of the translation in chapter 7
Merge pull request #483 from pepr/master

[cs] "Figure 1-1. xxx" replaced by the localized "Obrázek 1-1. xxx"
Merge pull request #481 from jukkah/master

[fi] Translated Chapter 2.4
Merge pull request #482 from GArik/RU-449

[ru] chapter 4: Improve wording in "Git Daemon" section
Merge pull request #435 from GArik/EN

[RFC] Extend/improve "Diffing Binary Files" section