Card:
* Parse MANUFACTURER card info value
* Add possibility to set manufacturer (e.g. for old versions of gpg)

OpenPGPCard, P15Card:
* Remove manufacturer
* Remove now obsolete overrides of operator==

ReaderStatus:
* Use fallback for guessing the OpenPGP card manufacturer from the
  serial number, if MANUFACTURER isn't included in card info
* For PKCS#15 cards this fallback isn't necessary

GnuPG-bug-id: 4876