Update release plan.

misc/plan.html

@@ -14,7 +14,7 @@
   <h1> Nettle release plans </h1>
   <p> This is an attempt at defining a development target for
   Nettle-2.8, inspired by similar pages for recent GMP releases. [Last
-  updated 2014-04-27]</p>
+  updated 2014-05-04]</p>
   <p class='should'>
     This really ought to be done before release
   </p>
@@ -113,13 +113,13 @@
   <p class='done'>
     Document new CCM mode.
   </p>
-  <p class='should'>
+  <p class='done'>
     Document new DSA interface.
   </p>
   <p class='should'>
     Document poly1305.
   </p>
-  <p class='should'>
+  <p class='done'>
     Document chacha.
   </p>