introducing FindBugs maven plugin to monitor production code for bugs/warnings + added annotations to SuppressWarnings on all existing warnings in production code (no warnings is actually fixed in this commit) + set the maven property findbugs.skip to false by default so that TravisCI will execute it; still UnitTests are not yet covered by FindBugs
Merge pull request #176 from YannRobert/IntroducingFindBugsMavenPlugin

introducing FindBugs maven plugin