emit error from google speech

[jaumard]

When Google Speech return an error, it's not emitted by sonus and we didn't know what append. This PR fix that

[evancohen]

Thanks @jaumard! Good idea :)

[jaumard]

No problem :) I think there some other problem around error management, I have no result/feedback when I have slow network :/

[evancohen]

I've had a tough time consistently reproducing that, but I've seen odd behavior on a slow network as well.
This fix addresses #34, but there might be more that we can do here for users with a slow connection - maybe just a configurable timeout?

[jaumard]

Hum in fact if I understand correctly the #34 that's what I fix with this PR, now sonus emit an error event with the error object given by the google speech module. But still have a problem in slow network maybe because it doesn't stop after a timeout and keep trying. So a configurable timeout should fix the problem but it must force quit the current connexion