Cleanup: upgrade requirements; remove deprecations; ...

[gggeek]

As part of the move to support eZPlatform 3, there is a fair amount of cleanup which can be accomplished:

• [ ] bump up minimum php version required
• [ ] bump up phpunit version in use
• [ ] drop the custom version of ezbehatbundle?
• [ ] remove deprecated php classes / constants / etc...

(and surely more)

[gggeek]

Closing as moved to the new project