[Console] Make sure formatter is the same

The parent constructor will create a new formatter if the $formatter parameter is null
This fix avoids that the formatter becomes 2 different instances in $this and $this->stderr
[Console] Add threshold for ProcessHelper verbosity
added XSD to PHPUnit configuration
Merge branch '2.3' into 2.4

* 2.3:
  bumped Symfony version to 2.3.18
  updated VERSION for 2.3.17
  update CONTRIBUTORS for 2.3.17
  updated CHANGELOG for 2.3.17
  added XSD to PHPUnit configuration
  bug #11319 [HttpKernel] Ensure the storage exists before purging it in ProfilerTest
  [Translation] Added unescaping of ids in PoFileLoader
  updated italian translation for validation messages
  [DomCrawler] Fix docblocks and formatting.
  [DomCrawler] Remove the query string and the anchor of the uri of a link
  Simplified the Travis test command
  [Console] Make sure formatter is the same

Conflicts:
	src/Symfony/Component/HttpKernel/Kernel.php
Merge branch '2.4' into 2.5

* 2.4:
  updated VERSION for 2.4.7
  updated CHANGELOG for 2.4.7
  bumped Symfony version to 2.3.18
  updated VERSION for 2.3.17
  update CONTRIBUTORS for 2.3.17
  updated CHANGELOG for 2.3.17
  added XSD to PHPUnit configuration
  add missing docblock for ProcessBuilder::addEnvironmentVariables()
  bug #11319 [HttpKernel] Ensure the storage exists before purging it in ProfilerTest
  [Translation] Added unescaping of ids in PoFileLoader
  updated italian translation for validation messages
  [DomCrawler] Fix docblocks and formatting.
  [DomCrawler] Remove the query string and the anchor of the uri of a link
  Simplified the Travis test command
  Remove Expression Language services when the component is unavailable
  [Console] Make sure formatter is the same

Conflicts:
	src/Symfony/Component/HttpKernel/Kernel.php
Merge branch '2.5'

* 2.5:
  updated VERSION for 2.4.7
  updated CHANGELOG for 2.4.7
  bumped Symfony version to 2.3.18
  updated VERSION for 2.3.17
  update CONTRIBUTORS for 2.3.17
  updated CHANGELOG for 2.3.17
  added XSD to PHPUnit configuration
  fix the return types
  add missing docblock for ProcessBuilder::addEnvironmentVariables()
  bug #11319 [HttpKernel] Ensure the storage exists before purging it in ProfilerTest
  [Translation] Added unescaping of ids in PoFileLoader
  updated italian translation for validation messages
  [DomCrawler] Fix docblocks and formatting.
  [DomCrawler] Remove the query string and the anchor of the uri of a link
  Simplified the Travis test command
  Remove Expression Language services when the component is unavailable
  Added SK translations
  [Console] Make sure formatter is the same
feature #11135 [FrameworkBundle] Use ProcessHelper for server:run command (romainneutron)

This PR was merged into the 2.6-dev branch.

Discussion
----------

[FrameworkBundle] Use ProcessHelper for server:run command

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT

Let's use our new process helper :)

Commits
-------

6ca1c90 [FrameworkBundle] Use ProcessHelper for server:run command
a5f36a8 [Console] Add threshold for ProcessHelper verbosity