- Feature: Allow to use RegisterExtension along with injected fields.
- Releng: Make sure that we run the testing.tests for Junit5 on Jenkins.
closeseclipse/xtext#1851
- provide new InjectionExtension as replacement for XtextRunner
- added unit test for InjectionExtension
- added JUnit 5 dependencies
Signed-off-by: Karsten Thoms <karsten.thoms@itemis.de>