3.4

Change log:
Issue #54: update to checkstyle 7.4
Issue #52: checkstyle-sonar-plugin does not work with sonar 4.5.2 and 4.5.4 require upgrade to 5.6.4
Issue #49: TC badge was added
Issue #48: findbugs is activated, but there are some cases to investigate in excludes
Issue #47: pmd is enforced on whole code
Issue #46: enforce strict code coverage by cobertura
Issue #45: Some Checvkstyle violations are resolved
Issue #44: upgrade to sonarqube 4.5.4 api
Issue #28: added test to verify checkstyle.properties