Fix export of Emote Anims

Bug in the registry key list refactor... We wrote out all the keys in the
key list instead of only the keys with objects. This meant we got a lot of
garbage (empty) objects when exporting [Fem|M]aleWave.

Sources/Plasma/PubUtilLib/plResMgr/plRegistryKeyList.cpp

@@ -217,15 +217,27 @@ void plRegistryKeyList::Write(hsStream* s)
     s->WriteLE32(0);
     s->WriteByte(0); // Deprecated flags
 
-    s->WriteLE32(fKeys.size());
+    // We only write out keys with data. Fill this value in later...
+    uint32_t countPos = s->GetPosition();
+    s->WriteLE32(0);
 
-    // Write out all our keys
+    // Write out all our keys with data
+    uint32_t keyCount = 0;
     for (auto it = fKeys.begin(); it != fKeys.end(); ++it)
-        (*it)->Write(s);
+    {
+        plKeyImp* key = *it;
+        if (key->ObjectIsLoaded())
+        {
+            ++keyCount;
+            key->Write(s);
+        }
+    }
 
-    // Go back to the start and write the length of our data
+    // Rewind and write out data size and key count
     uint32_t endPos = s->GetPosition();
     s->SetPosition(beginPos);
     s->WriteLE32(endPos-beginPos-sizeof(uint32_t));
+    s->SetPosition(countPos);
+    s->WriteLE32(keyCount);
     s->SetPosition(endPos);
 }