[CssSelector] fully rewritted component

Squashed commits:
[CssSelector] removed previous implementation
[CssSelector] rewriting, step 1
[CssSelector] rewriting, step 2
[CssSelector] rewriting, step 3
[CssSelector] rewriting, step 4
[CssSelector] rewriting, step 5
[CssSelector] rewriting, step 6
[CssSelector] fixed shortcuts regex
[CssSelector] tests, step1
[CssSelector] tests, step2
[CssSelector] tests, step3
[CssSelector] tests, step4
[CssSelector] fixed problems based @stof's on feedback
[CssSelector] tests, step5
[CssSelector] tests, step6
[CssSelector] tests, step7
[CssSelector] added my name in composer.json
merged branch jfsimon/css-selector-rewriting (PR #7463)

This PR was merged into the master branch.

Discussion
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[CssSelector] fully rewritted component

The `CssSelector` component is a port of the Python https://github.com/SimonSapin/cssselect library. Previous implementation was a port of the `v0.1` tag, this implementation is a port of the `v0.7.1` tag. As Python and PHP have different philosophies, this is not a simple language-to-language translation, I needed to re-architecture the lib.

**Note about BC:** This new version introduces some changes making fail legacy tests.
New XPath should be equivalents, these changes are:
-  When having a condition on an class, legacy condition is prefixed with a test of class existence. Example: `[contains(@class, 'foo')]` is transformed to `[@class and contains(@class, 'foo')]`.
-  When having conditions on descendants, `/descendant::*` is transformed to `/descendant-or-self::*/*`.

I updated legacy tests (stored in `CssSelectorTest` class) accordingly.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | yes
| BC breaks?    | see above
| Deprecations? | no
| Tests pass?   | yes

Should fix #3615 and #4271

Commits
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c6f87d0 [CssSelector] fully rewritted component
improved bytes conversion method
Add the serializer service
[CssSelector] removed unneeded use statements
[CssSelector] removed obsolete file
[CssSelector] fixed BC break
merged branch loalf/add_serializer_service (PR #6815)

This PR was merged into the master branch.

Discussion
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[2.3] [FrameworkBundle] [Serializer] Loads the Serializer component as a service in the Framework Bundle

This PR is the same as
https://github.com/symfony/symfony/pull/5347

but since I am struggling to squash all the commits I better create a new one. Sorry for the inconveniences, :)

Commits
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b4e4844 Add the serializer service
Added events for CLI commands

This adds an init and terminate event for commands. They are
dispatched from ContainerAwareCommand.

The cache:clear command can't implement this (cf. #3889 on Github).
added helperSet to console event objects
[Console] added a way to normalize a command display when using the tester
merged branch fabpot/console-tester-normalize (PR #7465)

This PR was merged into the master branch.

Discussion
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[Console] added a way to normalize a command display when using the tester

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

Commits
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afd7d05 [Console] added a way to normalize a command display when using the tester
refactored the implementation of how a console application can handle events
merged branch fabpot/console-dispatcher (PR #7466)

This PR was merged into the master branch.

Discussion
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Console dispatcher

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #3889, #6124
| License       | MIT
| Doc PR        | symfony/symfony-docs#2352

refs #1884, #1929

This is an alternative implementation for adding events to console applications.

This implementation has the following features:

* Available for anyone using the Console component and it is not tied to
  FrameworkBundle (this is important as one thing we are trying to solve is
  email sending from a command, and frameworks like Silex using the Console
  component needs a solution too);

* Non-intrusive as the current code has not been changed (except for renaming
  an internal variable that was wrongly named -- so that's not strictly needed
  for this PR)

* The new DispatchableApplication class also works without a dispatcher,
  falling back to the regular behavior. That makes easy to create applications
  that can benefit from a dispatcher when available, but can still work
  otherwise.

* Besides the *before* and *after* events, there is also an *exception* event
  that is dispatched whenever an exception is thrown.

* Each event is quite powerful and can manipulate the input, the output, but
  also the command to be executed.

Commits
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4f9a55a refactored the implementation of how a console application can handle events
4edf29d added helperSet to console event objects
f224102 Added events for CLI commands
merged branch jfsimon/issue-7413 (PR #7456)

This PR was merged into the master branch.

Discussion
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Improve bytes conversion method

This PR improves bytes conversion `regex` method introduced in #7413 (thanks to @vicb's comments).

* Adds support of `+` prefix.
* Adds support of blank chars between `+`, number and unit.
* Adds support of octal/hexa bases.

Notice that this can not be unit tested for `ServerParams` and `UploadedFile` classes because `ini_set()` function does not work with `post_max_size` and `upload_max_filesize` settings.

For information, this convertion is located in 3 classes:
* `Symfony\Component\Form\Extension\Validator\Util\ServerParams`
* `Symfony\Component\HttpFoundation\File\UploadedFile`
* `Symfony\Component\HttpKernel\DataCollector\MemoryDataCollector`

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7413

Commits
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21291ca improved bytes conversion method
[Form] fixed ServerParams::getPostMaxSize() regex pattern
merged branch jfsimon/issue-7480 (PR #7481)

This PR was merged into the master branch.

Discussion
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[Form] fixes ServerParams::getPostMaxSize() regex pattern

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7480

Commits
-------

84541e7 [Form] fixed ServerParams::getPostMaxSize() regex pattern
fixed bytes convertion method, again
merged branch jfsimon/issue-7481 (PR #7489)

This PR was merged into the master branch.

Discussion
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Fixes bytes convertion method, last episode

This definitely fixes the bytes convertion method.

@lazyhammer thanks for your support & indulgence
@fabpot sorry for the running gag
@vicb I opened a ticket: https://bugs.php.net/bug.php?id=64530

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #7481

Commits
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233b945 fixed bytes convertion method, again
Merge remote branch 'jfsimon/issue-6981' into issue-6981