Add JUnit4 support

[psoreide]

To prepare for bndtools/bndtools#377

[fhuberts]

@psoreide I see no tests for the new functionality? ;-)

[pkriens]

Does this still work in 1.4 environments?

[gravelld]

Is it possible to write a bnd selector for the Test-Cases header that chooses all the test classes given their JUnit4 annotations? ATM a selector is used that finds subclasses of TestCase (the JUnit 3 way).

[pkriens]

Guess so, you can try it with the ${classes} macro, it can query for annotations

[derheld42]

#398 also

[bjhargrave]

Junit 4 support is now in place.