[JENKINS-23185] Setting build status to FAILURE for new error when errors were fixed

- CppcheckBuildResultEvaluator.isErrorCountExceeded() used comparison count > threshold but users expect count >= threshold.
- For example the threshold had to be set to 0 to change build status on 1 new issue. Setting 1 in threshold configuration to detect 1 issue is much better.
- Information in build log extended to contain also the value that exceeded the threshold. Word "errors" replaced by "issues".
Merge pull request #20 from mixalturek/master

[JENKINS-23185] Setting build status to FAILURE for new error when error...