Add documentation about error handling

[ernestrc]

Is your feature request related to a problem? Please describe.
There is no documentation about error handling. In Nodejs, errors are handled by the runtime and bubbled up accordingly (termination with exit status and error message or emitted as an event on the global process emitter).

Describe the solution you'd like
We should add an entry to the wiki with a clear and concise description of how to handle errors.