Cpp: Add TofuInfo to signatures
* lang/cpp/src/tofuinfo.cpp, lang/cpp/src/tofuinfo.h: New class. * lang/cpp/src/verificationresult.cpp (Signature::tofuInfo): New. (VerificationResult::Private): Handle tofu info. (GpgME::operator<<(std::ostream &os, const Signature &sig)): Include TofuInfo in dump. * lang/cpp/src/verificationresult.h (Signature::tofuInfo): New. * lang/cpp/src/Makefile.am (main_sources, gpgmepp_headers): Add new files. * configure.ac (LIBGPGMEPP_LT_REVISION): Bump for new API.