maven: Use properties for dependency versions.
maven: Update apache parent to 16.
maven: Update maven-assembly-plugin to 2.5.2.
maven: Update maven-clean-plugin to 2.6.1.
maven: Update maven-compiler-plugin to 3.2.
maven: Update maven-javadoc-plugin to 2.10.1.
maven: Update maven-project-info-reports-plugin to 2.7.
maven: Update maven-site-plugin to 3.4.
maven: Update maven-surefire-plugin to 2.18.
maven: Update paranamer-maven-plugin to 2.7.
maven: Update sphinx-maven-plugin to 1.0.3.
Update commons-codec to 1.10.

This change is inoquous since code relevant to Flume was not change
between 1.8 and 1.10.
Update commons-compress to 1.9.
Update Gson to 2.3.1.