[HHVM-testing] Enable hhvm testing in .travis.yml
[HHVM-testing] Bump Doctrine-DBAL to 2.5beta & -Bundle to 1.3beta
[HHVM-testing] Change ConfigurationTest to mock class instead of interface

As interface declares __construct which does not work with hhvm
[HHVM-testing] Fix EzPublishCoreBundle/Tests/KernelTest to not mock DriverInterface
[HHVM-testing] Fix left over use of RichTextConverter\XsltConverter / XsdValidator