v2.4.0

• added BaseToken public API, this API enables advanced users in search of features such as JWT-formatted
  Bearer tokens or not being able to reconstruct client token values from a DB backup to overload
  these methods and get those features.
• fixed keystore initialize method to allow for servers only supporting authorization flow not needing
  RS256 signature key
• fixed token introspection disclosing details for expired but found tokens
• fixed exception during token introspection auth none clients looking up non-existing tokens