Centrifuge Fortuna v.0.0.3-alpha4 Release

Release notes:

• Document
  • Added Entity document type.
  • Updated Invoice/Purchase order document fields.
  • Simple Write ACLs on documents.
  • Document Consensus Validations.
  • Core Document changes.
• API
  • Added ability to define read and write collaborators on document.
  • New NFT InvoiceUnpaid endpoint.
  • Minor JSON response changes.
• Identity
  • Fixed concurrent identity creation
• Signature
  • Key revocation check