Adding google-formatter maven plugin support.

Formatting the files using the fmt-maven-plugin which uses
the google-format rules by default.  It will update your source
files during the process sources stage.

Change-Id: I1e2a8c58b5e4d47b211e5ef7be1675ada433af84

pom.xml

diff --git a/pom.xml b/pom.xml
index 93d4c7b..373052b 100644
--- a/pom.xml
+++ b/pom.xml
@@ -113,6 +113,19 @@
                     </execution>
                 </executions>
             </plugin>
+
+            <plugin>
+                <groupId>com.spotify.fmt</groupId>
+                <artifactId>fmt-maven-plugin</artifactId>
+                <version>2.25</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>format</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
         </plugins>
     </build>