Add option to not fail builds if a report is not found.

Useful in cases where one axis of a matrix build does not generate a CPP
check report.
Merge pull request #2 from niax/niax/allow-missing-report

Add option to not fail builds if a report is not found.
[maven-release-plugin] prepare release cppcheck-1.14
[maven-release-plugin] prepare for next development iteration