Twilio Client fails w/o a message

[caseysoftware]

When you don't set an Application Sid, the built in Twilio Client button doesn't work when you click it. Unfortunately, it doesn't give you an error message either, it just alternates red/green.

Ref: https://getsatisfaction.com/openvbx/topics/cannot_make_calls_via_web_client_no_message

[walker]

I fixed it from a UI perspective by not showing calling stuff when there's no application_sid available.

As for that library, it's hosted at static.twilio.com, not within this app.

[caseysoftware]

Closing this in favor of #231