* lang/cpp/src/context.cpp, lang/cpp/src/context.h
(Context::revokeSignature, Context::startRevokeSignature): New.
* lang/cpp/src/context.cpp
(getLFSeparatedListOfStrings, getLFSeparatedListOfUserIds): New.
(getLFSeparatedListOfFingerprintsFromSubkeys): Extracted second part
of function to getLFSeparatedListOfStrings.