Report Issues instead of Violations.

Use of 'Violation' class is deprecated since Sonar 3.6, and replaced with Issue; Context.saveViolation is replaced by Issuable.

This also allows properly counting the issues, i.e. accounting for disable rules and switched off violations.
Add a metric for dependencies violations.
Add line of include in cyclic dependency violation.
Create violation when the same file is explicitly included twice.
Merge remote-tracking branch 'tpz/violations'

Conflicts:
	sonar-cxx-plugin/src/main/java/org/sonar/plugins/cxx/compiler/CxxCompilerSensor.java
	sonar-cxx-plugin/src/main/java/org/sonar/plugins/cxx/cppcheck/CxxCppCheckSensor.java
	sonar-cxx-plugin/src/main/java/org/sonar/plugins/cxx/externalrules/CxxExternalRulesSensor.java
	sonar-cxx-plugin/src/main/java/org/sonar/plugins/cxx/pclint/CxxPCLintSensor.java
	sonar-cxx-plugin/src/main/java/org/sonar/plugins/cxx/rats/CxxRatsSensor.java
	sonar-cxx-plugin/src/main/java/org/sonar/plugins/cxx/utils/CxxReportSensor.java
	sonar-cxx-plugin/src/main/java/org/sonar/plugins/cxx/valgrind/CxxValgrindSensor.java
	sonar-cxx-plugin/src/main/java/org/sonar/plugins/cxx/veraxx/CxxVeraxxSensor.java
	sonar-cxx-plugin/src/test/java/org/sonar/plugins/cxx/TestUtils.java
	sonar-cxx-plugin/src/test/java/org/sonar/plugins/cxx/compiler/CxxCompilerSensorTest.java
	sonar-cxx-plugin/src/test/java/org/sonar/plugins/cxx/cppcheck/CxxCppCheckSensorTest.java
	sonar-cxx-plugin/src/test/java/org/sonar/plugins/cxx/externalrules/CxxExternalRulesSensorTest.java
	sonar-cxx-plugin/src/test/java/org/sonar/plugins/cxx/pclint/CxxPCLintSensorTest.java
	sonar-cxx-plugin/src/test/java/org/sonar/plugins/cxx/rats/CxxRatsSensorTest.java
	sonar-cxx-plugin/src/test/java/org/sonar/plugins/cxx/valgrind/CxxValgrindSensorTest.java
	sonar-cxx-plugin/src/test/java/org/sonar/plugins/cxx/veraxx/CxxVeraxxSensorTest.java