JUnit rule compatible with JUnit 4.7+

Fixes #140
test case compacted
review notes applied
Moved internal JUnitRule to better package
Simplified the JUnit specific handling
Pushed complexity to separate classes
Added a TODO
Ensured the next version is correct.
Reworked the public api for the Mockito JUnit rule.
Documented minimum JUnit for mockito rule
Deprecated MockitoJUnitRule

Fixes #139