Ensured that jax-rs tests bootstrap IOC container after setting client conf.
Added usage example to docs
Added a new injectable widget: TransitionAnchor to easily navigate to other errai-navigation @Pages
Merge branch 'master' into 3.0

Conflicts:
	errai-jaxrs/errai-jaxrs-client/src/main/java/org/jboss/errai/enterprise/client/jaxrs/test/AbstractErraiJaxrsTest.java
clustering support basic features now implemented.
make tests more reliable by using multi-stage latches