Clear entity manager before running each test to prevent wacky
side-effects.
Fixing problems with pageHiding() and IsWidget

For IsWidget pages 'pageHiding()' was called with the wrapped widget instead of the actual page.
updated documentation
Merge branch 'ERRAI-486-fix' of github.com:jbarop/errai into jbarop-ERRAI-486-fix

Conflicts:
	errai-navigation/src/test/java/org/jboss/errai/ui/nav/client/local/NavigationTest.java
Regression test for very long i18n strings (functionality was already working; just lacked tests)
Fixed ERRAI-611
Added tests for Service and Command Annotations
Set auto-discover-services=true to prevent failure of one of the test cases