CoreAssertions - interface with default implementations as a convenient entry point in Java 8

Hello, Joel.  I doubt you remember me, but we met very briefly at Devoxx France 2013.  I've been using AssertJ for a while, and I'm interested in gaining experience with Java 8 language features. I decided to implement David Gageot's idea of using an interface as the entry point for assertion calls, but in a way which doesn't break existing client code (using delegation). The advantage of using an interface goes beyond avoiding static imports.  One can create a subtype interface (ex : MyAssertions) which extends CoreAssertions to create a single entry point for all assertThat() calls, core and application-specific. In the future, some of the delegate calls in CoreAssertions could be replaced by calls using new Assertion classes that are specific to Java 8 (for example, assertions that accept method method references, or maybe assertions that provide Stream API's).