- upgrade nimbus-jose lib version to 2.15.1
- (ID-288) use RSA to sign JWS
  - store public key info in the JWS header ("kid" and "jku")
  - add url /1/jwkset to show public keys (as a JWK set)
- use symmetric encryption for JWE (only server reads it so there is no need for asymmetric enc)
- increase default config: prevent attribute verification after 5 failed tries (based on jit)
attributeBundle: move verified attributes inside "attrs:" block
- change attribute type "phone" to "phone_number"
bug fix: properly format verification pin in the twilio phone call message
- add simple encrypt and decrypt functions to Utility
- encrypt verificationPIN in the TwiML url (for twilio)
Merge pull request #12 from securekey/rsaAttributeBundle

jws and attribute bundle changes