Bumped version numbers of dependencies

* Bumped the version numbers for most dependencies
* Jetty updated to 9.2.6.v20141205
* Resteasy updated to 3.0.10.Final
* Hibernate updated to 4.3.7.Final
* Hibernate validator updated to 4.3.1.Final (had to stay on 4.x as the newest Resteasy doesn't seem to work on 5.x)
* Did not update the h2 and postgres dependencies
On startup there's still the following warning:
```
19:17:34.647 WARN  org.hibernate.ejb.HibernatePersistence - HHH015016: Encountered a deprecated javax.persistence.spi.PersistenceProvider [org.hibernate.ejb.HibernatePersistence]; use [org.hibernate.jpa.HibernatePersistenceProvider] instead.
```
Probably related to https://hibernate.atlassian.net/browse/HHH-9141