Update "Form type extension" cookbook for Symfony 2.2

Some deprecated calls where made and have been replaced by their newer counterparts.
Merge remote-tracking branch 'origin/fix/create_form_extension' into 2.3

Conflicts:
	cookbook/form/create_form_type_extension.rst
Merge pull request #376 from Greenflex/2.3

Update "form type extension" cookbook for Symfony 2.3
Update new_project_git.rst

Fix a path.
Move some tweaks of french language expressions.
Change "php bin/vendors install" into "composer".
Quelques erreurs corrigées

Quelques erreurs corrigées
Call of doctrine manager
Fixed hostname_pattern: it's host

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | 2.2+
Merge pull request #377 from n1c01a5/patch-1

Update new_project_git.rst
Merge pull request #380 from younesherlock/master

Updated css_selector.rst : fixed an error
Merge pull request #379 from amine26tz/patch-1

Call of doctrine manager
Merge pull request #382 from MarieMinasyan/patch-1

Fixed hostname_pattern: it's host
Merge pull request #383 from symfony-fr/2.3

Merging 2.3 to 2.4
Merge pull request #384 from symfony-fr/2.4

Merging 2.4 to master