Remove bitdeli Badge

Bitdeli tracking doesn't work. See http://blog.bitdeli.com/post/77717727361/on-githubs-image-proxy
Merge pull request #38 from bameda/master

Remove bitdeli Badge
Upgrade to Grails 2.4.0
Update grails wrapper to 2.4.0
Use a new non-deprecated PostgresqlDialect
Now all integration tests extends from Specification
Upgrade all user types to be Hibernate 4 compatible
Update criterias to be Hibernate 4 compatible
Add coveralls plugin with Travis integration