Update README.md

 simple-rtmp-server
 ==================
 
-simple rtmp origin/edge live server over state-threads.<br/>
+simple rtmp origin live server over state-threads.<br/>
 can be used as origin server, or rtmp-server for encoder.
 
 1. simple: also stable enough.
 2. high-performance: single-thread, async socket, event/st-thread driven.
-3. support origin and edge mode.
+3. support origin only, no edge mode.
 4. only for live streaming.
 5. donot support vhost, \_\_defaultVhost\_\_ only.
 6. single process, no multiple processes yet.