Return the default PMD rule sets instead of an empty list.

Fixes #33 and also fixes the names/location of the default PMD rule
sets ('java/basic.xml' instead of 'java-basic.xml').

Signed-off-by: Sebastian Hoß <mail@shoss.de>
Fixed rule set location & naming

Signed-off-by: Sebastian Hoß <sebastian.hoss@ysura.com>
FindBugs: All bugs categories must be visible by default
FindBugs: Enable all detectors by default.

Description of visitors from findbugs site:

It specifies a comma-separated list of bug detectors which should be
run. The bug detectors are specified by their class names, without any
package qualification.

By default, all detectors which are not disabled by default are run.
Setup findbugs for check goal too
Merge pull request #34 from sebhoss/default_pmd_rule_sets

Return the default PMD rule sets instead of an empty list.
Merge pull request #38 from NEXSTEP/master

Findbugs defaults
Merge pull request #41 from ArloL/patch-1

Setup findbugs for check goal too