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
[cs] Typos and formulation changes in Ch. 1 up to 1.3 included.
Translating "Applying a Patch with am"
Reviewed "Distributed Git"
Reviewed "Distributed Git"
Merge branch 'chapter04'
Reviewed "Distributed Workflow"
Reviewed "Centralized Workflow"
Reviewed "Integration-Manager Workflow"
Reviewed "Dictator and Lieutenants Workflow"

wrong title translation
typo
Reviewed "Dictator and Lieutenants Workflow"
Reviewing "Contributing to a Project"
Reviewing "Contributing to a Project"
Reviewing "Contributing to a Project"
Reviewed "Contributing to a Project"
Reviewing "Commit Guidelines"

commit è femminile
Update 01-chapter5.markdown

Fixed typo.