Adjust README for new mdserver functionality

README.md

@@ -15,7 +15,9 @@ Alternate MDX research project
 Reads source metadata file(s) and outputs them signed to filesystem
 
 ## ```mdserver.py [mdfile] [mdfile] [mdfile] ...```
-Reads source metadata files(s). Serves and caches them signed from memory, on request
+Starts a metadata signer server.
+Reads source metadata files(s) on SIGHUP signal.
+Serves and caches them signed from memory, on request
 
 ## ```mdproxy.py```
 Caches signed and cached ```mdserver.py``` metadata requests