curl_easy_exception doesn't set any message into std::exception

[KingDuckZ]

In my main() function I have a try/catch block that catches std::exception. When I print err.what() the output is just "exception", and the original message "Couldn't connect to server" is lost.
I don't want to include curlcpp files in my main.cpp, so I can't access the original exception type.

[JosephP91]

@KingDuckZ this should now be fixed in #129.