Provide support for hibernate 5

[ptahchiev]

Just as a follow-up on this one:

https://jira.spring.io/browse/DATAREST-545

I don't think the project works with hibernate5. Hibernate5 beta2 is out already - please verify the project works and implement if it doesn't :)

[cowtowncoder]

Implemented via #68

[cowtowncoder]

One comment: due to major version upgrade, there is now new hibernate5 sub-module (similar to hibernate3 and hibernate4), as well matching Hibernate5Module.java.