Reorder definitions to avoid a forward reference.

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

protocol/protocol.tex

@@ -338,6 +338,10 @@ $\CryptoBoxSpecific$) \cite{cryptobox} as follows.
 \end{bytefield}
 \end{lrbox}
 
+Let $\TransmitPublicNew{1..\NNew}$ be the Curve25519 public keys for the intended
+recipient addresses of each new \coin, and let $\Plaintext{1..\NNew}$ be their
+\coinPlaintexts.
+
 Define:
 
 \begin{itemize}
@@ -345,10 +349,6 @@ Define:
 \CryptoBoxSealHashbox{\noncebox}$.
 \end{itemize}
 
-Let $\TransmitPublicNew{1..\NNew}$ be the Curve25519 public keys for the intended
-recipient addresses of each new \coin, and let $\Plaintext{1..\NNew}$ be their
-\coinPlaintexts.
-
 Then to encrypt:
 
 \begin{itemize}