Include findbugs-contrib rules

[RichardBradley]

While findbugs code has a good base set of rules, most of Findbug's bug patterns are defined in findbugs-contrib.

It looks to me like findbugs4sbt doesn't include findbugs-contrib by default. Is that correct?

If so, we should probably add it by default (or at least add easy to follow instructions to the docs on how to include).

[HairyFotr]

As a workaround you can put the plugin jars into the ~/.findbugs/plugin folder.

Tested with fb-contrib and findsecbugs.

[josephearl]

You can use pluginList now with https://github.com/lenioapp/sbt-findbugs-plugin