v2.2.0

(NEW) Added support for modeling SPARQL property paths (#49)
(NEW) Added support for declaring SPARQL prefixes (#54)
(FIX) ID of pattern group should only be based on its name (#53)
(FIX) Representation of reserved XML namespace breaks xml compatibility (#50)
(MISC) Code formatting compliant with Microsoft policies
(MISC) Code cleanups, improvements and internal architecture redesigns