Add new event in putblic API

[Dmitriy Govorukhin]

HI all, I think what we need add new event for handling
unhandled exception. We have some exception which not handled, new
event (UnhandledExceptionEvent) can
help know if was unhandled exception. Let's discuss. More details about
reason IGNITE-2079 <https://issues.apache.org/jira/browse/IGNITE-2079>