Added skipping of PASSED in console / added more help on mutiple Excludes/Includes

The clamav plugin is great!
The thing is, that it is very noisy in the console, since every file is displayed in the console. I've added a switch consoleTraceOnlyWarningsOrErrors which gives the jenkins admin the possibility to disable the expected default "PASSED" and only displays INFECTED or SKIPPED.

Additionally I've more help for multiple excludes and includes for the user. The doc of ANT isn't very helpful to see how multiple excludes/includes should work.

And it would be nice if you could mention my name for the addition ;-)