Fixing receiving MediaUrl parameter from Twilio.
Debugging
Created image proxy to account for Twilio MediaUrl redirect.
Fixed image proxy for Twilio unescaping image_url too many times, and not keeping proxy url escaped, when sent as parameter.
Allow sending test messages to self by prepending text body with ~.
Updated Twilio SMS endpoint to new endpoint that supports MMS.
Remove image proxy, use original twilio mms urls.