ERRAI-740: Linker for permutation specific cache manifest files
Offline linker now generates manifest per user agent (not per permutation)
Addition to ERRAI-740: Servlet that provides user agent specific manifests
Make sure linkers don't cause deployment issues in dev mode
Fix RPC interceptor chaining bug with async interceptor creation.
Use RestClient domain and path when setting cookies for JAX-RS CookieParam.
Update GWT to version 2.6.1.

Some expected test-behaviour in errai-jaxrs and errai-data-binding needed to be changed.
The guava version was also upgraded to avoid gwt compilation errors in errai-navigation.