Refactored Configurator to ease addition of new steps

Fixes #90
Update SymfonyRequirements.php

Adapt the cache and logs permission requirements to the 3.0 structure
fix missing console file with symfony3 directory structure
bug #133 Update SymfonyRequirements.php (mmf-amarcos)

This PR was merged into the 3.0.x-dev branch.

Discussion
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Update SymfonyRequirements.php

Adapt the cache and logs permission requirements to the 3.0 structure

Commits
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02bfcf7 Update SymfonyRequirements.php
fixed CS
Fix syntax error in SymfonyRequirements.php
bug #136 Fix syntax error in SymfonyRequirements.php (pyrech)

This PR was merged into the 3.0.x-dev branch.

Discussion
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Fix syntax error in SymfonyRequirements.php

Commits
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3c15b6a Fix syntax error in SymfonyRequirements.php
Fix phpunit.xml.dist in new directory structure
bug #137 Fix phpunit.xml.dist in new directory structure (pyrech)

This PR was squashed before being merged into the 3.0.x-dev branch (closes #137).

Discussion
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Fix phpunit.xml.dist in new directory structure

- [X] The bootstrap setting of phpunit wasn't updated in the new directory structure.
- [X] We need to add the `<php><server name="KERNEL_DIR" value="app/" /></php>` part because the [KernelTest::getKernelClass()](https://github.com/symfony/symfony/blob/master/src/Symfony/Bundle/FrameworkBundle/Test/KernelTestCase.php#L101) search by default the Kernel in the same directory than phpunit.xml.dist, which is not the case anymore

Any opinion on this @fabpot or @romainneutron?

Commits
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f31f061 Fix phpunit.xml.dist in new directory structure
bug #134 bugfix: missing console file with symfony3 directory structure (yeka)

This PR was merged into the 3.0.x-dev branch.

Discussion
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bugfix: missing console file with symfony3 directory structure

When creating a new project with Symfony3 directory structure, <code>bin/console</code> is not found in commit list (get ignored). Therefore when the commit is cloned, <code>bin/console</code> file is missing.
nb: my os is windows

Commits
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fb6219d fix missing console file with symfony3 directory structure
[Composer] removed unused variable
minor #143 [Composer] removed unused variable (hhamon)

This PR was merged into the 3.0.x-dev branch.

Discussion
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[Composer] removed unused variable

Commits
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e7706d8 [Composer] removed unused variable
removed APC as a suggestion as OpCache is the default now in PHP 5.5+
Changed a hard coded path to a root directory
minor #130 Changed a hard coded path to a root directory (hason)

This PR was merged into the 3.0.x-dev branch.

Discussion
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Changed a hard coded path to a root directory

A vendor folder can be customized - https://getcomposer.org/doc/04-schema.md#config Composer is run in a root directory.

Commits
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5101428 Changed a hard coded path to a root directory
SymfonyRequirements.php: add filter requirement
minor #122 SymfonyRequirements.php: add filter requirement (glensc)

This PR was squashed before being merged into the 3.0.x-dev branch (closes #122).

Discussion
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SymfonyRequirements.php: add filter requirement

filter extension should be enabled, or you may get such error when validating:

UndefinedFunctionException: Attempted to call function "filter_var" from namespace "Symfony\Component\Validator\Constraints"

Commits
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f2b8d1d SymfonyRequirements.php: add filter requirement
Removed undefined constant ScriptHandler::NEW_STRUCTURE_NOTIFIER

Fixed #138
bug #145 Removed undefined constant ScriptHandler::NEW_STRUCTURE_NOTIFIER (pyrech)

This PR was merged into the 3.0.x-dev branch.

Discussion
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Removed undefined constant ScriptHandler::NEW_STRUCTURE_NOTIFIER

Fixed #138

The constant `ScriptHandler::NEW_STRUCTURE_NOTIFIER` was used on [`Resources/bin/build_bootstrap.php#L49`] (https://github.com/sensiolabs/SensioDistributionBundle/blob/master/Resources/bin/build_bootstrap.php#L49). This constant was temporarily created - then removed - during the development of the PR #118.

Commits
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284e1fa Removed undefined constant ScriptHandler::NEW_STRUCTURE_NOTIFIER
Making the 3.0 directory structure question not asked unless you have a constant