Add a JUnit Rule as alternative to JUnit Runner

Add EasyMockRule to process annotation-driven mocking re-using the same
injection routine established for EasyMockRunner.
Update JavaDoc for EasyMockRule

Correct some JavaDoc with references to EasyMockRule
Add license header
Extract JUnit Statement as top level class

Extract JUnit Statement from EasyMockRunner as a top-level class for
re-use in EasyMockRule
Merge pull request #2 from Todderz/simple-rule

JUnit Rule to process mocking annotations as per EasyMockRunner JUnit Runner