Download JAR files tagged by xmlelement with all dependencies

Plugin to add @XmlElement(nillable=false) if nillable=false and minoccurs=0 is set in xsd to help Jackson

When generating XML schema from Java source code using the schemagen tool a common approach is to use the @XmlElementWrapper and @XmlElement annotations to handle schema generation for collections. However, when generating Java source from a schema using the xjc tool the resulting code is not created with these annotations. Instead, the generated Java source contains "injected" inner classes to accommodate the collection of elements contained within an element.