improved bytes conversion method
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
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
----------

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
-------

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
----------

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
-------

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
----------

[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