v0.4.0

Added

• stringify and parse functions for generating and parsing Siren JSON

Changed

• Object creation now done via static factory methods (e.g., Entity.of({...}))
• Validation is now done via class-validator
• Renamed Entity's and Action's get* methods to find*

Removed

• Query methods:
  • Entity.prototype.getActionsByClass()
  • Entity.prototype.getEntitiesByClass()
  • Entity.prototype.getLinksByClass()