Test/fixes to handle NULL pointer for unique_ptr/auto_ptr

Also add missing unique_ptr tests for Lua and Racket.

Examples/test-suite/python/cpp11_std_unique_ptr_runme.py

@@ -77,6 +77,11 @@ if not is_nullptr(kini):
 del kini # Should not fail, even though already deleted
 checkCount(0)
 
+takeKlassUniquePtr(None)
+takeKlassUniquePtr(make_null())
+checkCount(0)
+
+
 # unique_ptr as output
 k1 = makeKlassUniquePtr("first")
 k2 = makeKlassUniquePtr("second")
@@ -90,3 +95,6 @@ if k2.getLabel() != "second":
 
 del k2
 checkCount(0)
+
+if (makeNullUniquePtr() != None):
+  raise RuntimeError("null failure")