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
[nl] Revised earlier Dutch translation

Modified certain sentences and wordchoises to be (hopefully) more
consistent with actual use of jargon in Dutch.
[nl] Revised earlier Dutch translation

Modified certain sentences and wordchoises to be (hopefully) more
consistent with actual use of jargon in Dutch.
Merge branch 'chapter01' of github.com:Cpt-xx/progit into chapter01
Merge pull request #640 from progit-de/master

[de] Enhance section 9
Merge pull request #638 from Cpt-xx/chapter01

Chapter01 Dutch version
[es] Fixed semantics errors
Merge branch 'BrodaNoel-semanticerrors'
Fix misspellings
Merge pull request #643 from wojtekk/patch-1

Fix misspellings
[zh] Change font of pdf format to 'WenQuanYi Micro Hei', which looks better
Merge pull request #644 from riccoyu/master

[zh] Change font of pdf format to 'WenQuanYi Micro Hei', which looks bet...
[nl] Retranslate chapter 03

Reshuffle wording and sentences. Replace some Babelfish type translations
with more sensible translations. Introduce diacritics to enhance clarity.
Update command line output in Chapter 2

The command line output in the examples is from an older version of Git
(1.7.*) and is slightly inconsistent with the latest version.
Merge pull request #646 from Cpt-xx/chapter03

[nl] Retranslate chapter 03
Merge pull request #645 from Matt-Stevens/update-commandline-output-ch2

Update command line output in Chapter 2
[nl] Retranslate chapter 05, first phase

Replace strange character sequences with actual diacritics and hyphens.
[nl] Retranslate chapter.

	Reword and remove a number of Babelfishes in the text.
	Introduce diacritics.