deepcopy and pickle support for TypedSymbol and Field.Access

field.py

@@ -226,6 +226,9 @@ class Field:
 
             return obj
 
+        def __getnewargs__(self):
+            return self.name, self.offsets, self.index
+
         __xnew__ = staticmethod(__new_stage2__)
         __xnew_cached_ = staticmethod(cacheit(__new_stage2__))
 

typedsymbol.py

@@ -24,3 +24,7 @@ class TypedSymbol(sp.Symbol):
         superClassContents = list(super(TypedSymbol, self)._hashable_content())
         t = tuple(superClassContents + [hash(self._dtype)])
         return t
+
+    def __getnewargs__(self):
+        return self.name, self.dtype
+