enable parallel check of languages

Use parallel to spawn as many subprocesses as possible to accelerate
the tests.
Change Maruku check to fully functional mode

this is cleans up the code.
Force output of Rake messages to stderr
[zh] fix branch name half translate to chinese
[ko] translation update

[ko] translation update ch1 to ch4

[ko] translation update ch5

[ko] translation update ch6

[ko] translation update ch7

[ko] translation update ch8

[ko] translation update ch9

[ko] proofreading.

[ko] fix mistyping.
[ko] update translation.

Conflicts:
	ko/03-git-branching/01-chapter3.markdown
	ko/04-git-server/01-chapter4.markdown
	ko/07-customizing-git/01-chapter7.markdown
Merge pull request #525 from CatTail/master

[zh] fix branch name half translate to chinese
Merge pull request #526 from dogfeet/ko

[ko] update translation.
perhaps little typo

"Modifici" is not an Italian word, maybe "Modifica"
Typo in word "gender"

"è stato aggiunto" not "è stato aggiunta"
perhaps little typo

"Modifici" is not an Italian word, maybe "Modifica"
Grammar error

"quale ramo" is correct, "quale rame" is not
Command typo

`git co` is correct, `git ci` is not
Reset last commit

`git ci` was correct, instead of `git co`
Merge pull request #527 from Zorgatone/patch-1

perhaps little typo
Merge pull request #528 from Zorgatone/master

[IT] - Minor language grammar fixes
Added German expressions for chapter, section, etc.
Merge pull request #529 from 1aschroe/master

Added German expressions for chapter, section, etc.
translate gitolite segment into chinese
Merge pull request #530 from omytea/master

translate gitolite segment into chinese