Fix errors when opening the talent viewer while not having a spec selected (fixes #13)

Author: Numynum

TalentTreeViewer_TWW/TalentViewer.lua

@@ -241,7 +241,7 @@ end
 function TalentViewer:InitSpecSelection()
     local _, _, classId = UnitClass('player');
     local currentSpec = GetSpecialization() or 1;
-    local specId = cache.specIndexToIdMap[classId][currentSpec];
+    local specId = cache.specIndexToIdMap[classId][currentSpec] or cache.specIndexToIdMap[classId][1];
     TalentViewer:SelectSpec(classId, specId);
 end
 

TalentTreeViewer_TWW/mixins/TalentViewerUIMixin.lua

@@ -292,6 +292,15 @@ function TalentViewerUIMixin:GetAndCacheNodeInfo(nodeID)
     return GetOrCreateTableEntryByCallback(self.nodeInfoCache, nodeID, GetNodeInfoCallback);
 end
 
+function TalentViewerUIMixin:GetAndCacheSubTreeInfo(subTreeID)
+	local function GetSubTreeInfoCallback()
+        self.dirtySubTreeIDSet[subTreeID] = nil;
+		return LibTalentTree:GetSubTreeInfo(subTreeID)
+	end
+
+	return GetOrCreateTableEntryByCallback(self.subTreeInfoCache, subTreeID, GetSubTreeInfoCallback);
+end
+
 function TalentViewerUIMixin:GetAndCacheCondInfo(condID)
     local function GetCondInfoCallback(condID)
         local condInfo = {