DATACMNS-391 - Ensure compatibility with Spring Framework 4.0.

Some tests required an explicit dependency to servlet-api-3.x.
The GenericApplicationContext doesn't refresh automatically in Spring 4.x we thus we have to call refresh manually. Added a specific version of populators.xml for Spring 4.x since the jaxb2-marshaller element definition no longer renamed the contextPath attribute to context-path in 4.x.

Original pull request: #52.
DATACMNS-391 - Mitigate changes between Spring 3 and 4' GenericTypeResolver.

As of Spring 4, the GenericTypeResolver is more consistent in detecting raw types. It now returns null for both resolveTypeArguments(Set.class, Set.class) as well as resolveTypeArguments(Set.class, Iterable.class). The latter returns an array of Object.class in 3.x.

As this shouldn't make a pratical difference to actual clients (as they need to check for null anyway, we loosen the test case to be able to build Spring Data Commons against both Spring 3 and Spring 4.

Some polishing in the version detection in integration tests. Moved the Servlet 3.0 dependency into the Spring 4 profile.
DATACMNS-384 - Polished toString() representation of Version.

Trailing zeros now get removed up until the minor version number.