Support testing against multiple versions of findbugs.
Format pom.
Don't add plugin config files to classpath by default. To avoid this bug: https://sourceforge.net/p/findbugs/bugs/1201/
Don't add plugin config files to classpath by default. To avoid this bug: https://sourceforge.net/p/findbugs/bugs/1201/
Change source and target level to match FindBugs.