Add style check exclusion rule example

- Remove ProtoBuf generated code from findbugs,checkstyle,pmd.
- Workaround for findbugs issue running findbugs:findbugs goal
- Added notes to cross-reference others

Change-Id: I5d23b61480a2bdba8d27d6ed0d92728021c240a2
diff --git a/conf/findbugs/exclude.xml b/conf/findbugs/exclude.xml
new file mode 100644
index 0000000..b6a240a
--- /dev/null
+++ b/conf/findbugs/exclude.xml
@@ -0,0 +1,14 @@
+<FindBugsFilter>
+     <!--
+        Note: Exclusion definition exists in multiple places.
+        - In file ${findbugs.excludeFilterFile} defined at top of pom.xml (this file)
+        - maven-checkstyle-plugin configuration in pom.xml
+        - maven-pmd-plugin configuration in pom.xml
+     -->
+     <Match>
+       <Class name="~net.onrc.onos.datastore.RCProtos(.*)?" />
+     </Match>
+     <Match>
+       <Class name="~com.tinkerpop.blueprints.impls.ramcloud.RamCloudGraphProtos(.*)?" />
+     </Match>
+</FindBugsFilter>