Add explicit serialVersionUID to subclasses of AbstractStatistic
Clear ehcaches before and after each JPA test
Update and fix administration tests

- Use assertj instead of hamcrest
- remove change username test (invalid)
- add admin change user password test
- formatting cleanup
Merge pull request #494 from zanata/update-to-assertj-admin

Update and fix administration tests
Merge pull request #490 from zanata/serialid-wordstat

Add explicit serialVersionUID to subclasses of AbstractStatistic