another couple notes

src/per_curve/eddsa.tmpl.hxx

@@ -34,6 +34,7 @@ class PrivateKey;
 class PublicKey;
 /** @endcond */
 
+/** Prehash context for EdDSA.  TODO: test me! */
 class Prehash : public $(re.sub(r"SHAKE(\d+)",r"SHAKE<\1>", eddsa_hash.upper())) {
 public:
     /** Do we support contexts for signatures?  If not, they must always be NULL */
@@ -211,6 +212,8 @@ public:
     /** The pre-expansion form of the signature */
     FixedArrayBuffer<$(C_NS)_EDDSA_PUBLIC_BYTES> pub_;
     
+    /* PERF FUTURE: Pre-cached decoding? Precomputed table?? */
+    
 public:
     /** Underlying group */
     typedef $(cxx_ns) Group;