Make sure that after_reading is called when loading a Symbol. This fixes #68

src/data/symbol.cpp

@@ -335,6 +335,9 @@ void Symbol::after_reading(Version v) {
   SymbolGroup::after_reading(v);
   updateBounds();
 }
+void after_reading(Symbol& symbol, Version v) {
+  symbol.after_reading(v);
+}
 
 double Symbol::aspectRatio() const {
   // Margin between the edges and the symbol.

src/data/symbol.hpp

@@ -293,7 +293,9 @@ public:
   
   DECLARE_REFLECTION_OVERRIDE();
   void after_reading(Version) override;
+  friend void after_reading(Symbol&, Version);
 };
+void after_reading(Symbol&, Version);
 
 /// A default symbol: a square
 SymbolP default_symbol();