As of Spring 4.3 RC1 the `org.aopalliance` interfaces are once again bundled
with `spring-aop` [1]. Moreover, all modules with a dependency on
`aopalliance:aopalliance` directly or indirectly also depend on `spring-aop`.
This change drops the `aopalliance:aopalliance` dependency in all places it's
declared. Where applicable an explicit dependency on `spring-aop` was added in
its place. (This dependency was already present in most places; in one case the
module didn't require `aopalliance:aopalliance` in the first place.)
The documentation is updated accordingly.
[1] https://jira.spring.io/browse/SPR-13984