Refactor|Model Renderer: Revised definition syntax for state triggers

It is more intuitive if the state is the parent record. Multiple
possible sequences can be defined per state (maybe with different
probabilities). One sequence may also be used in several states.

doomsday/client/net.dengine.client.pack/testmodel.pack/Info

@@ -7,9 +7,8 @@ asset model.thing.possessed {
     path = "boblampclean.md5mesh"
 
     group animation {
-        sequence "#0" {
-            state = POSS_STND
-            timeline <0, 5, 10>
+        state POSS_STND {
+            sequence "#0" { timeline <0, 5, 10> }
         }
     }
 }

doomsday/client/src/render/modelrenderer.cpp

@@ -75,15 +75,25 @@ DENG2_PIMPL(ModelRenderer)
             // Prepare the animations for the model.
             QScopedPointer<StateAnims> anims(new StateAnims);
 
-            Record const &animDef = asset.accessedRecord().subrecord(DEF_ANIMATION);
-            Record::Subrecords subs = animDef.subrecords();
+            // TODO: Add a utility method for getting subrecords of particular type (ScriptedInfo).
+
+            Record::Subrecords subs = asset.accessedRecord().subrecord(DEF_ANIMATION).subrecords();
+
             DENG2_FOR_EACH_CONST(Record::Subrecords, i, subs)
             {
-                // Is this an animation sequence?
                 Record const &def = *i.value();
-                if(def.gets("__type__", "") == "sequence" && def.has("state"))
+                if(def.gets("__type__", "") == "state")
                 {
-                    (*anims)[def.gets("state")] << AnimSequence(i.key(), def);
+                    Record::Subrecords seqs = def.accessedRecord().subrecords();
+
+                    DENG2_FOR_EACH_CONST(Record::Subrecords, s, seqs)
+                    {
+                        Record const &seqDef = *s.value();
+                        if(seqDef.gets("__type__", "") == "sequence")
+                        {
+                            (*anims)[i.key()] << AnimSequence(s.key(), seqDef);
+                        }
+                    }
                 }
             }