Update description to match.

Author: sobomax

README.md

@@ -3,7 +3,8 @@
 # Sippy B2BUA
 
 Sippy B2BUA is a [RFC3261](https://www.ietf.org/rfc/rfc3261.txt)-compliant
-Session Initiation Protocol (SIP) [Back-to-back user agent](http://en.wikipedia.org/wiki/Back-to-back_user_agent) (B2BUA).
+Session Initiation Protocol (SIP) stack and
+[Back-to-back user agent](http://en.wikipedia.org/wiki/Back-to-back_user_agent) (B2BUA).
 
 The Sippy B2BUA is a SIP call controlling component. Unlike a SIP proxy server,
 which only maintains transaction state, the Sippy B2BUA maintains complete call