SONAR-5237 - moved DB part of stack to sonar-core
Merge branch 'master' of https://github.com/SonarSource/sonarqube

# By Julien Lancelot (2) and Stas Vilchik (1)
# Via Stas Vilchik
* 'master' of https://github.com/SonarSource/sonarqube:
  Component Viewer: duplications
  Ignore some failing tests
  Fix licence headers

Conflicts:
	sonar-core/src/main/java/org/sonar/core/cluster/LocalNonBlockingWorkQueue.java
	sonar-server/src/main/java/org/sonar/server/rule2/RuleConstants.java
	sonar-server/src/main/java/org/sonar/server/rule2/RuleDao.java
	sonar-server/src/main/java/org/sonar/server/rule2/RuleIndex.java
	sonar-server/src/test/java/org/sonar/server/rule2/RuleIndexTest.java
Merge branch 'master' of https://github.com/SonarSource/sonarqube

# By Julien Lancelot
# Via Julien Lancelot
* 'master' of https://github.com/SonarSource/sonarqube:
  Fix quality flaws
Adding NullQueue for sonar-batch
Merge branch 'master' of https://github.com/SonarSource/sonarqube

# By Jean-Baptiste Lievremont
# Via Jean-Baptiste Lievremont
* 'master' of https://github.com/SonarSource/sonarqube:
  SONAR-4927 Merge new QG widget with old one, update layout
SONAR-5237 - fixed with IT tests for batch and server