This class is provided to specify a generic pair name-value object, this value may be used by the framework with several objectives.
They provide a generic mechanism to configure a component with no specific API.
For instance to specify custom structures used in lists, tables or trees ("artifacts").
@author Jose Maria Arranz Santamaria
@see org.itsnat.comp.ItsNatComponent#getArtifact(String)
@see org.itsnat.core.ItsNatDocument#getArtifact(String)
@see org.itsnat.core.tmpl.ItsNatDocumentTemplate#getArtifact(String)
@see org.itsnat.core.ItsNatServletConfig#getArtifact(String)
@see org.itsnat.comp.ItsNatComponentManager#createItsNatComponent(Node,String,NameValue[])