Always start a sender number with + on twillio

lib/plugins/sms/twilio/twilio.js

@@ -14,11 +14,13 @@ function sendMessage (account, rec) {
       const client = twilio(account.accountSid, account.authToken)
       const body = rec.sms.body
       const _toNumber = rec.sms.toNumber || account.toNumber
+      const from = _.startsWith('+')(account.fromNumber)
+        ? account.fromNumber : `+${account.fromNumber}`
 
       const opts = {
         body: body,
         to: _toNumber,
-        from: account.fromNumber
+        from
       }
 
       return client.messages.create(opts)