Add ezpublish-kernel to frameworks.yaml

This is related to effort in https://github.com/ezsystems/ezpublish-kernel/pull/735 to add HHVM support in eZ Publish, one of the more advanced CMS systems in PHP.

Currently exposes several issues like DateTime issues, ArrayObject issues, XML namespace issues and others which has not been identified yet.

# Example failures

Failures most likely caused by HHVM behaving differently then Zend engine.

## Datetime

```
4) eZ\Publish\Core\FieldType\Tests\PageTest::testToHash with data set #1 (, array('2ZonesLayout1', array(array('6c7f907b831a819ed8562e3ddce5b264', 'left', array(array('1e1e355c8da3c92e80354f243c6dd37b', 'Campaign', 'Campaign', 'default', '', '6c7f907b831a819ed8562e3ddce5b264', array(array(10, 20, 30, 'Thursday, 01-Jan-70 00:00:01 GMT+0000', 'Thursday, 01-Jan-70 00:00:02 GMT+0000', 'Thursday, 01-Jan-70 00:00:03 GMT+0000', 'Thursday, 01-Jan-70 00:00:04 GMT+0000', '67dd4d9b898d89733e776c714039ae33', 'modify', '594491ab539125dc271807a83724e608', array('value'))), array('value2'))), array('value3'))), array('value4')))
toHash() method did not create expected result.
Failed asserting that two arrays are equal.
--- Expected
+++ Actual
@@ @@
                             'priority' => 30
-                            'publicationDate' => 'Thursday, 01-Jan-70 00:00:01 GMT+0000'
-                            'visibilityDate' => 'Thursday, 01-Jan-70 00:00:02 GMT+0000'
-                            'hiddenDate' => 'Thursday, 01-Jan-70 00:00:03 GMT+0000'
-                            'rotationUntilDate' => 'Thursday, 01-Jan-70 00:00:04 GMT+0000'
+                            'publicationDate' => 'Thursday, 01-Jan-70 00:00:01 CET'
+                            'visibilityDate' => 'Thursday, 01-Jan-70 00:00:02 CET'
+                            'hiddenDate' => 'Thursday, 01-Jan-70 00:00:03 CET'
+                            'rotationUntilDate' => 'Thursday, 01-Jan-70 00:00:04 CET'
                             'movedTo' => '67dd4d9b898d89733e776c714039ae33'
                             'action' => 'modify'
                             'blockId' => '594491ab539125dc271807a83724e608'
                             'attributes' => Array (...)
                         )
                     )
                     'attributes' => Array (...)
                 )
             )
             'attributes' => Array (...)
         )
     )
     'attributes' => Array (...)
 )
```

and

```
10) eZ\Publish\Core\Persistence\Legacy\Tests\Content\Type\Gateway\DoctrineDatabaseTest::testLoadGroupData
Failed asserting that two arrays are equal.
--- Expected
+++ Actual
@@ @@
 Array (
     0 => Array (
-        'created' => '1031216941'
+        'created' => '1033922113'
         'creator_id' => '14'
         'id' => '2'
         'modified' => '1033922113'
         'modifier_id' => '14'
         'name' => 'Users'
     )
 )
```

## ArrayObject

```
5) eZ\Publish\SPI\Tests\FieldType\DateIntegrationTest::testLoadContentTypeField
eZ\Publish\API\Repository\Exceptions\PropertyNotFoundException: Property 'defaultType' not found on class 'eZ\Publish\Core\FieldType\FieldSettings'

/home/vagrant/ezpublish-kernel/eZ/Publish/Core/FieldType/FieldSettings.php:54
/home/vagrant/ezpublish-kernel/eZ/Publish/Core/Persistence/Legacy/Content/FieldValue/Converter/Date.php:96
/home/vagrant/ezpublish-kernel/eZ/Publish/Core/Persistence/Legacy/Content/Type/Mapper.php:362
/home/vagrant/ezpublish-kernel/eZ/Publish/Core/Persistence/Legacy/Content/Type/Mapper.php:209
/home/vagrant/ezpublish-kernel/eZ/Publish/Core/Persistence/Legacy/Content/Type/Mapper.php:120
/home/vagrant/ezpublish-kernel/eZ/Publish/Core/Persistence/Legacy/Content/Type/Handler.php:251
/home/vagrant/ezpublish-kernel/eZ/Publish/Core/Persistence/Legacy/Content/Type/Handler.php:196
/home/vagrant/ezpublish-kernel/eZ/Publish/Core/Persistence/Legacy/Content/Type/MemoryCachingHandler.php:155
/home/vagrant/ezpublish-kernel/eZ/Publish/SPI/Tests/FieldType/BaseIntegrationTest.php:317
```

## XML namespace

´´´
2) eZ\Publish\Core\FieldType\Tests\RichTextTest::testToPersistenceValue
eZ\Publish\Core\Base\Exceptions\NotFoundException: Could not find 'Validator' with identifier ''

/home/vagrant/ezpublish-kernel/eZ/Publish/Core/FieldType/RichText/ValidatorDispatcher.php:79
/home/vagrant/ezpublish-kernel/eZ/Publish/Core/FieldType/RichText/Type.php:168
/home/vagrant/ezpublish-kernel/eZ/Publish/Core/FieldType/FieldType.php:391
/home/vagrant/ezpublish-kernel/eZ/Publish/Core/FieldType/Tests/RichTextTest.php:216
´´´