fix bug where create_note_from_template can be called without calendar info

lua/telekasten.lua

@@ -281,6 +281,11 @@ local function calculate_dates(date)
 end
 
 local function linesubst(line, title, dates)
+    
+    if dates == nil then
+      dates = calculate_dates()
+    end
+
     local substs = {
         hdate = dates.hdate,
         week = dates.week,