update maven-javadoc-plugin with -Xdoclint:none.

Show these are errors with -Xdoclint:all. 
With JDK 8, you are unable to get Javadoc unless your tool meets the
standards of doclint. Some of its rules are:

- no self-closed HTML tags, such as <br /> or <a id="x" />
- no unclosed HTML tags, such as <ul> without matching </ul>
- no invalid HTML end tags, such as </br>
- no invalid HTML attributes, based on doclint's interpretation of W3C
HTML 4.01
- no duplicate HTML id attribute
- no empty HTML href attribute
- no incorrectly nested headers, such as class documentation must have
<h3>, not <h4>
- no invalid HTML tags, such as List<String> (where you forgot to escape
using &lt;)
- no broken @link references
- no broken @param references, they must match the actual parameter name
- no broken @throws references, the first word must be a class name

Note that these are errors, not warnings. Break the rules and you get no
javadoc output. See:
http://blog.joda.org/2014/02/turning-off-doclint-in-jdk-8-javadoc.html

pom.xml

@@ -164,6 +164,10 @@
 						</goals>
 					</execution>
 				</executions>
+				<configuration>
+                    <!--  -Xdoclint:all -->
+                    <additionalparam>-Xdoclint:none</additionalparam>
+                </configuration>
 			</plugin>
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>