Update HushList protocol whitepaper some more

whitepaper/protocol.tex

@@ -876,12 +876,17 @@ various blockchains and using various software stacks. The design of \HushList i
 
 \nsection{Reference Implementation}
 
-The reference implementation is developed as Free Software on Github at the following URL:
+The reference implementation is developed as Free Software under the GNU Public License Version 3 on Github at the following URL:
 
 https://github.com/leto/hushlist
 
 This code is still in active development, consider it EXPERIMENTAL and ONLY FOR DEVELOPERS at this point pending a security review.
 
+The current reference implementation can send and receive memos, including files on disk or simple strings of text, as long as they are up to 512 bytes.
+
+Multipart sends and public HushLists are still in development.
+
+
 \nsection{Account Funding}
 
 On first run, \HushList creates a new shielded zaddress $z_F$ to fund transparent addresses for pseudonymous sending.