Update minimum Spring version to 4.x (#283)
Update minimum Spring version to 4.x (#283)

See:

* https://github.com/togglz/togglz/issues/282
* https://github.com/springtestdbunit/spring-test-dbunit/issues/46

Fixes: #282
togglz/togglz,togglz/togglz,togglz/togglz