Exceptions not being handled with libuv: bug or what?

[dadadanix]

I couldn't find anything about `nimTestErrorFlag`, so I supposed it was like a 
built-in function initially. As a I said previously a possible solution to make 
the program handle the exception is to stop the event loop by calling 
`uv_stop`, but I couldn't find a way to add a global exception handler, so I 
think the only way for now is to manually stop it before an exception is thrown