Fixes to Receiving SMS Replies

* Since we're saving phone numbers as 'numeric' in the database we need to remove non-numeric characters before comparing any phone numbers
* We're also using strrpos to compare 'sender' and 'from' because some people might use '000-000-0000' in their sms config vs '+10000000000'. Both work. **strrpos** allows us to compare two numbers in case one doesn't have the country code. Twilio is obviously US biased.
* Append the '+' in the Twilio send() as the phone number is stored as numerical for consistency

@ekala -- need a review