Remove ProtoBuf from OTASCIIArmor

Remove unused aliases, fix order of methods.
Merge pull request #432 from OttoAllmendinger/pr-noprotobuf

Remove ProtoBuf from OTASCIIArmor
Message/API rename: checkUser -> checkNym.
Message rename: notarizeTransactions -> notarizeTransaction.
Message/API rename: getAccountFiles -> getAccountData.