Workaround for MNG-3244

Child modules inherit their parent's URL, etc. by appending their own
artifactId to the parent URL.
This assumes that each parent/child dependency is hierarchical. This is
not the case for my projects.
Added JDT-based compiler

The maven-compiler-plugin now uses the JDT compiler which is configured
to use the global compiler settings inside the common-resources project.
Defined additional properties
Downgrade maven-jar-plugin

The newer versions throws an error in a multi-module build.
Version updated
Configuration for GitHub pages

Call mvn site-deploy to create & deploy a site to github
Added parent for Java-based projects