backport 44936fd to other language and pdf

This change needs to be backported to all languages. The pdf toolchain
processes this formula with a transformation to some latex mathematic
typesetting and therefore needs to be updated.
[nl] Chapter 09 - Review and retranslate where necessary.
Update 01-chapter3.markdown

simple typo: Du kann mehrere Branches -> Du kannst mehrere Branches
Merge pull request #687 from Sicaine/patch-1

Update 01-chapter3.markdown
Merge pull request #686 from Cpt-xx/chapter09

[nl] Chapter 09 - Review and retranslate where necessary.
[nl] All chapters - Add header and SHA-1 of current HEAD

	Added SHA-1 of current head to be used in future to
	allow for easier (hopefully) comparison of changes in
	en - original texts.
Merge pull request #689 from Cpt-xx/synchVersions

[nl] All chapters - Add header and SHA-1 of current HEAD
[zh] Update Chapter 5
Merge pull request #690 from biluncloud/master

[zh] Update Chapter 5
[de] Drop trailing spaces
[de] Apply changes from 'en' original
add 03-git-branching
update to 3-8
finish 3-1
Update 01-chapter3.markdown
Update 3.2
3.2 word error
chapter 3 finished
add Chapter 4
chapter 5 finished