Support for class-level validation

This allows for

    $errorElement->addConstraint(new UniqueEntity(['fields' => 'email']));

and similar code without an enclosing ->with().
The preg_replace() /e modifier is deprecated from PHP5.5.0.
FOSUB github URL changed
Merge pull request #1430 from andreadelfino/translation-it

Updated italian translation
documentation update on sonata_type_collection
Merge pull request #1432 from tiagojsag/collection_type_docs

documentation update on sonata_type_collection
Fix breadcrumbs for custom routes when subject is empty

Hi. When I open my custom routes, there is no label in breadcrumbs for it, because subject is empty.
Update configuration.rst

the sonata_admin.templates section wasn't full (it's now aligned with Templates documentation page)
Update templates.rst

sonata_admin.templates.dashboard was missing
Merge pull request #1443 from net02/patch-2

Updated documentation
wrap nav menu in block for easier customization
Merge pull request #1441 from tiagojsag/menu_block

Wrap nav menu in block for easier customization
Merge pull request #1422 from xianhuazhou/master

The preg_replace() /e modifier is deprecated from php5.5.0. Instead, use the preg_replace_callback() function.
Merge pull request #1436 from fluxuator/master

Fix breadcrumbs for custom routes when subject is empty
PR for Issue #1291. Support of the custom prototype names
Merge pull request #1448 from fluxuator/feature-custom-prototype-name

PR for Issue #1291. Support of the custom prototype names
use ~ syntax in composer.json dependencies
Merge pull request #1451 from lsmith77/composer_tweaks

use ~ syntax in composer.json dependencies
fixed BlockBundle dependency
Merge pull request #1452 from lsmith77/composer_tweaks

fixed BlockBundle dependency