Add clients to initial and test data, show in view
Make Client.id attribute public
Add markup in index view for adding a Client to an Invoice
Merge with 'develop'
Fix PersistenceException: not adding @MappedSuperclass to AbstractModel
Remove unnecessary @Required fields in Client
Let ClientTest inherit BaseModelTest
Fix incorrect call to Client#find
Remember to save newly created client object in ClientTest
Use latest sbt (0.13.0)
Use dynamic Play version for sbt-plugin
Use @ManyToMany mapping for Invoice-Client
Fix failing User test
Generate DB evolution
Remove unused imports
Adjust index.html to avoid nullpointer
Merge with Johan's branch