List of changes from upstream sources:

- vendor/singpolyma/openpgp-php/lib/openpgp.php

  Split output armor text every 76 characters (OpenPGP::enarmor()).
  Fix determining message structure when attempting to verify User ID
  signatures (OpenPGP_Message#signatures()).
  Fix ignoring a 0x30 byte (OpenPGP_Packet#read_byte()).
  Fix computing signatures for v3 packets (OpenPGP_SignaturePacket#read()).

- vendor/singpolyma/openpgp-php/lib/openpgp_crypt_rsa.php

  Don't alias Math\BigInteger as Math_BigInteger.

- vendor/singpolyma/openpgp-php/lib/openpgp_crypt_symmetric.php

  Added support for using the openssl extension to parse CAST128 data
  (OpenPGP_Crypt_Symmetric::getCipher()).
  Added support for the Blowfish and Twofish ciphers
  (namespace import, constants, OpenPGP_Crypt_Symmetric::getCipher()).
