maven java9 profile:
- use maven-javadoc-plugin version 3.0.0-M1, because versions below 3.0.0 do not work on java 9
- skip maven-coveralls-plugin, because version 4.3.0 does not work on java 9, see https://github.com/trautonen/coveralls-maven-plugin/issues/112
This patch copies the FindBugs configuration in pom.xml from the
reporting section to the build section so findbugs can be used as part
of the build process (by using the maven goal findbugs:check).
It then adds this goal to the Travis CI build so that FindBugs
becomes part of the CI, and new patches would be prevented from
introducing new FindBugs errors.
Currently, checkstyle is only run as part of the reporting phase, and
it's up to the developer to check the report manually.
This patch adds the checkstyle configuration to the build plugins so
it can be used to check the code (as opposed to just generate a
report of the failures) and adds it to Travis CI's configuration so
every new patch will be automatically checked against it.