Output the analysis to an external file

By providing an <tt>outputFileName</tt> we can now redirect the analysis output to a file in CSV format.

this can be handy when processing a large number of maven modules and redirecting the output to a single file.

<tt>for i in ./app* ; do mvn -f ${i}/pom.xml -DoutputFileName=C:/data/analysis/apps-filtered.txt com.ning.maven.plugins:maven-duplicate-finder-plugin:1.0.8-SNAPSHOT:check; done</tt>