quick fix: added missing console message forwarding for when readium-sdk errors are raised (EPUB parsing, exceptions, etc.) This error handler should be implemented in all native launchers, otherwise the console remains silent when testing erroneous EPUBs.

See: https://github.com/readium/SDKLauncher-OSX/commit/3de14b9c7f3654c2cd7aeda977cc82b1003fb496