[JENKINS-22965] Cppcheck plugin shall display the inconclusive messages

- Inconclusive flag present in cppcheck report is parsed, stored and displayed in results.
- Headers are highlighted (bold) in the listing of all issues.
[JENKINS-22965] Cppcheck plugin shall display the inconclusive messages

- Inconclusive messages are displayed with gray text color.
[JENKINS-22965] Cppcheck plugin shall display the inconclusive messages

- Item "inconclusive" added to XSD schema, this should solve a broken build (generated file was updated).
Merge pull request #16 from mixalturek/master

[JENKINS-22965] Cppcheck plugin shall display the inconclusive messages