8.4.0 - hello-sparnatural

This release corresponds to some refactoring of the source folders, most notably the introduction of the hello-sparnatural folder as a basis for a getting-started guide for documentation.
It also corresponds to significant improvements in SHACL support for configuration, although not yet documented.

Breaking change:

• #501 and #500 and #502 : changed the language behavior by introducing a defaultLang init parameters, passed to the datasources and honored by the defaultLabel properties

New features:

• #499 : new init event passing the languages of the configuration
• #509 : set default limit parameter to -1

Bug fixes:

• #506 : add bif prefix in default Virtuoso datasource
• #508 : drop support of declaring datasources on classes

Documentation:

• #503 : Document SPARQL proxy URL at http://docs.sparnatural.eu/SPARQL-proxy.html